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CRUISE REPORT:  CBL
(Last Update NOV 2010)

1.  HIGHLIGHTS

CRUISE SUMMARY INFORMATION

                 Section Designation  CBL
   Expedition designation ExpoCodes)  32PZ20020819
                     Chief Scientist  Rebecca Woodgate, University of Washington
                               Dates  2001 AUG 19 - 2002 SEPT 23
                           Ship  R/V  UCSCGC Polar Star
                       Ports of call  Barrow, Alaska

               Geographic Boundaries               80° 14.5' N
                                      152° 20' W                174° 14' E
                                                    74° 30' N

                  Number of stations  126
        Floats and drifters deployed  0
     Moorings depoloyed or recovered  3 deployed and recovered

                     Chief Scientist Contact Info:

           Rebecca Woodgate & Knut Aagaard • Applied Physics Laboratory
     University of Washington • 1013 NE 40th Street, Seattle, WA 98105, U.S.A
            Email: woodgate@apl.washington.edu • Phone: 206-221-3268



CHUKCHI BORDERLAND CRUISE
CBL 2002
Arctic West - Phase II (AWS-02-II)



USCGC Polar Star
Cruise Leader: Rebecca Woodgate, University of Washington
Barrow, Alaska, 19th August -Barrow, Alaska, 23rd September 2002


NSF Arctic Natural Sciences OPP-0117480 


University of Washington, Scripps Institution of Oceanography 
Lamont-Doherty Earth Observatory, Oregon State University



2.  SUMMARY 

Some 600 miles north of the Bering Strait, 800 miles south of the North Pole, 
the entrance into the Arctic Ocean is marked by a complex area of tortuous 
topography known as the Chukchi Borderland. This region of slopes, ridges, 
and deep-sea plateaus is an Arctic Crossroads, where waters from the Pacific 
and from the Atlantic meet. 

The Atlantic waters (warmer and saltier) flow cyclonically (anticlockwise) 
from Fram Strait and the Barents Sea around the edges of the Arctic Basins 
and approach the Mendeleev Ridge and the Chukchi Borderland from the west. 
The Pacific waters (colder, fresher and high in nutrients) enter at a 
shallower depth from the south via Bering Strait and the Chukchi Sea. Past 
measurements suggest that the pathways of both waters split in the Borderland 
region. Some waters continue cyclonically along the Beaufort slope, whilst 
some leave the boundary and head into the deep basin. The processes 
determining the splitting and the pathways, presumably depending upon the 
winds, the ice, the sea floor topography and thermohaline forcing, are 
neither well measured nor understood. The pathways of these waters have 
implications for local ecosystems (c.f. the nutrient-rich Pacific waters) and 
climate (c.f. the warm Atlantic layer), and also global ocean circulation 
issues (c.f. transit times through the Arctic Ocean). 

A 35-day NSF-sponsored cruise aboard the USCGC Polar Star has studied in 
depth the physical oceanography of the Chukchi Borderland and Mendeleev Ridge 
regions. An extensive hydrographic survey (126 CTD casts) was conducted. In 
addition to CTD profiles of temperature, conductivity, oxygen, and light 
scatter and L-ADCP profiles of water velocity, bottle samples were taken for 
nutrients (2662 samples), dissolved oxygen (2999 samples), salinity (3066 
samples) and tracers CFCs (F11, F12, F113, ca. 2500 samples), O18 isotopes 
(ca.1000 samples), Barium (ca.1000 samples), Helium (ca.108 samples), Iodine-
129 (96 samples) and Cesium-137 (27 samples). Twenty-one denitrification 
(N:Ar ratio) samples were also taken. A total of 47 XBTs were used both to 
increase spatial coverage over the shelf and to increase spatial resolution 
in the slope regions. To better map the boundary current regime, 3 
oceanographic moorings carrying current meters and temperature and salinity 
sensors were deployed across the boundary current for the ca. 1 month 
duration of the cruise. During the cruise, via a website of daily updates 
from a High School teacher aboard the Polar Star and visits to schools in 
Barrow, we brought Arctic research into the classroom. Post-cruise a multi-
institute team of scientists will study this extensive data set, with 
reference to previous (sparse) measurements, Canadian measurements taken this 
year in the Canadian Basin and near Northwind Ridge, and modeling results, to 
understand the role of this Arctic Crossroads in the circulation of the 
Arctic Ocean.

CBL2002 CRUISE TRACK

Cruise track in pink. Depth contours are "Terrainbase" and only approximate. 
Section numbering is as per proposal. Moorings are located on section 2. CTD 
stations are marked as black dots. XBTs are marked as black crosses.

CTD (red dots, right) and XBT (blue crosses, left) positions superimposed 
upon schematic topography.


PARTICIPANTS
_____________________________________________________________________________

Scientific Personnel:
-----------------------------------------------------------------------------
Rebecca Woodgate (PI)    University of Washington   Chief Scientist
Knut Aagaard (co-PI)     University of Washington   Moorings and CTD
Jim Swift (co-PI)        SIO                        CTD
Jim Johnson              University of Washington   Moorings
Ron Patrick              SIO                        CTD(Technician in Charge)
Scott Hiller             SIO                        CTD (salts)
John Calderwood          SIO                        CTD (oxygens)
Susan Becker             SIO                        Nutrients
Dave Muus                SIO                        CTD Bottle samples
Mary Johnson             SIO                        CTD data processing
Eugene Gorman            LDEO                       CFCs
Guy Mathieu              LDEO                       CFCs
Sarah Zimmermann         LDEO (UAF)                 CFCs
Kevin Vranes             LDEO                       CFCs
Kellie Balster           University of Washington   CTD (N:Ar, Cs, I)
Wendy Ermold             University of Washington   CTD (LADCP, He) 
Marlene Jeffries         University of Washingon    CTD (O18 and Ba) 
Gail Grimes              Lake Stevens High School   CTD, Educational outreach
-----------------------------------------------------------------------------
Ship's Personnel:
-----------------------------------------------------------------------------
CAPT Dave Mackenzie      Commanding Officer 
CDR Bruce Toney          Executive Officer 
LT Matthew Walker        Operations Officer 
ENS Rebecca Albert       Marine Science Officer 
MST1 El McFadden
MST3 Bryan Klostermeyer, 
Lee Brittle,
April Dalton
BM3 Darrell Bresnahan, 
SM Megan Crawford
-----------------------------------------------------------------------------
Science Participants not aboard: 
-----------------------------------------------------------------------------
Bill Smethie (co-PI)     LDEO                       CFCs 
Kelly Falkner (co-PI)    Oregon State University    O18, Ba 
Peter Schlosser          LDEO                       He 
John Smith               Bedford Institute, Canada  Cs and I 
Mark Ortmeyer            University of Washington   Website 
Ed Carmack               IOS, Sidney, Canada        CTD 
Fiona McLaughlin         IOS, Sidney, Canada        CTD 
Al Devol                 University of Washington   N:Ar 
_____________________________________________________________________________



3.  SCIENTIFIC BACKGROUND 

The most important subsurface Arctic Ocean transport system, a cyclonic (here 
anticlockwise) boundary current, organized along the continental slopes and 
major trans-Arctic ridges, distributes waters, tracers and contaminants from 
the Atlantic (via Fram Strait and the Barents Sea) and the Pacific (via 
Bering Strait) around and into the deep Arctic basins. On its circum- Arctic 
pathway, parts of the topographically steered current are diverted away from 
the continental margin, generally along topographic ridges. The most complex 
obstacle the boundary current encounters is the Mendeleev Ridge/Chukchi 
Borderland complex, north of the Pacific entrance to the Arctic. This region 
is the cross-roads for Pacific-origin waters from the south and Atlantic 
waters carried from the west with the boundary current. The tortuous 
bathymetry offers many routes for a topographically steered current, and the 
spatial variability of the sparse data that exist clearly indicates the 
complexity of the region. These data also show significant interannual 
variability, in line with the major changes seen in the last decade 
throughout the Arctic, and they further suggest that the region diverts 
significant amounts of water into the deep basins, indicating this region's 
importance to shelf-basin exchange, deep basin ventilation, and circum- and 
trans-Arctic circulation (with feedback implications to the World Ocean 
circulation). Yet, the pathways and exchanges in this area are still unclear, 
both qualitatively and quantitatively, due to the lack of sufficiently 
concentrated observations. The purpose of this research cruise was to conduct 
a high spatial resolution hydrographic and tracer survey, supported by short-
term moored current and CTD measurements, in the region of the Chukchi 
Borderland and the southern end of the Mendeleev Ridge during 
August/September 2002. 

Our objectives are to: 

  •  delineate the pathways of the boundary current carrying the Atlantic water 
     past the Mendeleev Ridge and through the Chukchi Borderland; 
  •  ascertain the input from the boundary current and the shelves to the deep 
     Arctic Ocean in the vicinity of the Mendeleev Ridge and the Chukchi 
     Borderland; 
  •  understand and quantify the pathways and transformations of the Pacific 
     waters through this region; 
  •  describe the horizontal and vertical structure of the boundary current, and 
     estimate its transport; and 
  •  quantify recent temporal changes in this region by combining the spatially 
     sparse data extending through most of the past decade with new detailed 
     synoptic measurements. 

On the 35-day expedition on the USCGC Polar Star, we have measured 
temperature, salinity, dissolved oxygen, nutrients, CFCs, Ba and O18, on 14 
sections that cross both the boundary flow and the Pacific inputs to the 
region before and after topographic junctions and hypothesized regions of 
flow diversion. Subsections of water samples were also taken for Helium, Cs-
137, I-129, and N:Ar ratios. This tracer suite will allow us to identify the 
pathways of the boundary current and the Pacific-origin waters, and to 
quantify the different Atlantic and Pacific influences, as well as freshwater 
input from ice melt and different rivers. In addition, three moorings were 
deployed, spanning the boundary current for the duration of the cruise. 
Current meters and moored conductivity and temperature sensors quantify the 
vertical and horizontal extent of the boundary current, its structure and 
variability, and will yield an estimate of the transport and a description of 
eddies carried with or across the boundary current. To give a comprehensive 
picture of the system, the entire data set will be analyzed collectively and 
in tandem with hydrographic, tracer, and moored time series data from the 
last decade. Since the transit time of signals through this region is 2-4 
years, the older data provide a temporal background for the new high spatial 
resolution data, whilst the newer data will supply an essential spatial 
framework for understanding the variability of the older surveys. 

The work will yield a substantially increased understanding of the role of 
this region in the Arctic circulation, including a determination of pathways, 
a quantification of exchanges, and an assessment of temporal change. Its 
timing in 2002 provides a high quality hydrographic survey of the western 
Arctic at a time when the most dramatic changes ever observed in the Arctic 
are propagating through this region. The project will provide necessary 
background and mechanistic information to the SEARCH and Arctic-Subarctic 
Ocean Flux programs, and essential far-field information to the SBI Phase II 
field program in the Chukchi and Beaufort seas. Our cruise track also 
dovetails with the Canadian Arctic Expeditions this summer. In addition, the 
results will be pivotal to validating and improving high resolution computer 
and conceptual models of the Arctic, and will offer insights to physical 
mechanistic problems, such as the driving mechanism of the boundary current 
and the interaction of an equivalent barotropic current with steep and sharp 
topography.




4.  HYDROGRAPHIC MEASUREMENTS PROGRAM 
    (Jim Swift, Knut Aagaard, Ron Patrick, Scott Hiller, Susan Becker, Mary      
    Johnson, Dave Muus, John Calderwood, Kellie Balster, Marlene Jeffries, 
    Wendy Ermold, Gail Grimes) 

The hydrographic measurements program was run by the SIO group to WHP 
standards specifications or higher. Extracts from the preliminary report (Feb 
2003) is included below. 

In brief, 126 CTD/rosette casts were taken to within ca.10m of the bottom. 
Down- and up-cast profiles of temperatures, conductivity, pressure, dissolved 
oxygen and light scatter were recorded. Seabird sensors were used for T, C 
and oxygen. The light scattering sensor was made by WetLabs. Only the 
downcast data is presented in the final data. CTD data is good to 0.2 db, 
0.0002deg C and 0.005 mS/cm. 

Apart from winch interference issues on the early casts (causing some spiking 
in the CTD data), no major problems were encountered during the operation. 

Water samples were taken from a 36 place rosette system, bottle depths being 
chosen with reference to the CTD and oxygen profiles. Samples were taken for 
CFCs, Helium, dissolved oxygen, salinity, O18 isotopes, barium, Iodine-129, 
Cesium-137 and N:Ar ratios. Not all samples were taken at all bottles or all 
casts.


(EXTRACT from ODF Preliminary Cruise Report)

4.1.  Description of Measurement Techniques 

The basic hydrography program consisted of salinity, dissolved oxygen and 
nutrient (nitrite, nitrate, phosphate and silicate) measurements made from 
bottles taken on CTD/rosette casts, plus pressure, temperature, salinity and 
dissolved oxygen from CTD profiles. 126 CTD/rosette casts were made, usually 
to within 10 meters of the bottom. One additional cast was aborted by the 
bridge (station 66 cast 1) at ~90 meters due to ice problems; it is not 
reported. No major problems were encountered during the operation. The 
distribution of samples is illustrated in figures 4.1.0-4.1.4. 


Figure 4.1.0: Sample distribution, stations 1-13.
Figure 4.1.1: Sample distribution, stations 13-34.
Figure 4.1.2: Sample distribution, stations 34-76.
Figure 4.1.3: Sample distribution, stations 76-106.
Figure 4.1.4: Sample distribution, stations 107-126.


4.2.  WATER AND SAMPLING PACKAGE 

CTD/rosette casts were performed with a system consisting of a 36-bottle 
rosette frame (ODF), a 36-place pylon (SBE32) and 36 10-liter PVC bottles 
(ODF). Underwater electronic components consisted of a Sea-Bird Electronics 
(SBE) 9plus CTD (ODF #381) with dual conductivity and temperature sensors, 
SBE43 oxygen sensor, WetLabs Light Scattering Sensor (LSS), dual RDI LADCPs 
and Simrad altimeter. 


Table 4.2.0:  Underwater sampling package.
_____________________________________________________________________________

36-bottle rosette frame           ODF                s/n unknown 
Bullister 10-liter bottles        ODF                1-36 
36-place Carousel Water Sampler   Sea-Bird           s/n 113 
Deck Unit (in lab)                Sea-Bird SBE11     s/n 292 (USCG) 
ODF CTD #381                      Sea-Bird SBE9plus  s/n 09P9852-0381 
  Pressure                        Paroscientific     s/n 58952 
                                  Digiquartz         
  Temperature#1                   Sea-Bird SBE3plus  s/n 03P-2505 
  Temperature#2                   Sea-Bird SBE3plus  s/n 03P-2380 
  Conductivity#1                  Sea-Bird SBE4C     s/n 04-1919 
    (stas 1-48) Conductivity#2    Sea-Bird SBE4C     s/n 04-2023 
    (stas 50-126) Conductivity#2  Sea-Bird SBE4C     s/n 04-1549 
  Oxygen Sensor                   Sea-Bird SBE43     s/n 43-0185 
Pump for T1/C1/Oxygen Sensors     Sea-Bird SBE5T     s/n unknown 
Pump for T2/C2 Sensors            Sea-Bird SBE5T     s/n unknown 
Light Scattering Sensor           WetLabs LSS        s/n CST-477 
Altimeter                         Simrad 807         s/n 9711091 
LADCPs                            RDI 300KHZ         s/n unknown 
LADCP Battery Pack                WHOI
_____________________________________________________________________________


CTD #381 was mounted horizontally along the bottom of the rosette frame. The 
altimeter reported distance-above-bottom. The dissolved oxygen sensor and 
altimeter were interfaced with the CTD, and their data were incorporated into 
the CTD data stream. The two LADCPs were vertically mounted to the frame 
inside the bottle rings, one each at the top and bottom of the rosette, with 
upward- and downward-looking transducers. The rosette system was suspended 
from a three-conductor 0.322" electromechanical cable. Power to the CTD and 
pylon was provided through the cable from a SBE11plus deck unit in the lab. 
The USCGC Polar Star's portside InterOcean CTD winch was used throughout the 
leg. 

The deck watch prepared the rosette approximately 45 minutes prior to each 
cast. All valves, vents and lanyards were checked for proper orientation. The 
bottles were cocked and all hardware and connections rechecked. Time, 
position and bottom depth were logged by the console operator at arrival on 
station. The rosette was moved into position under a projecting boom from the 
port-side CTD hangar using an overhead trolley. Two stabilizing tag lines 
were threaded through rings on the frame, and CTD sensor covers were removed. 
As directed by the USCGC watch leader, the winch operator raised the package, 
extended the J-frame boom over the side of the ship and quickly lowered the 
package into the water; then the tag lines were removed. 

Each rosette cast was lowered to within 7-20 meters of the bottom. Bottles on 
the rosette were identified with unique serial numbers. These numbers 
corresponded to the pylon tripping sequence 1-36, the first trip closing 
bottle #1. No bottles were changed out during the leg, although parts of 
bottles may have been replaced or repaired. 

Averages of CTD data corresponding to the time of bottle closure were 
associated with the bottle data during a cast. CTD pressure, depth, 
temperature, salinity, density and oxygen were immediately available to 
facilitate examination and quality control of the bottle data as the sampling 
and laboratory analyses progressed. 

Recovering the package at the end of deployment was essentially the reverse 
of launching, with the additional use of poles and snap-hooks to attach tag 
lines for added stabilization. The rosette was moved into the CTD hangar for 
sampling. The bottles and rosette were examined before samples were taken, 
and anything unusual was noted on a sample log for each cast. 

Routine CTD maintenance initially included soaking the conductivity and CTD 
O2 sensors in distilled water between casts to maintain sensor stability. 
After station 27, the sensors were rinsed in discarded IAPSO standard 
seawater after each cast, but not soaked, due to problems with water freezing 
in the sensor pump tubing. After station 50, when the substitute secondary 
conductivity sensor was installed, tygon tubing was placed between the ducts 
and pumps of the primary and secondary sensor housings to keep the sensors 
and pump tubes warmer while on deck. The rosette was stored in the CTD hangar 
between casts to insure the CTD was not exposed to direct sunlight, wind or 
snow, in order to maintain the internal CTD temperature near ambient air 
temperature. A large space heater, which could be aimed at the sensors, was 
used as needed in the hangar after station 27 to keep the sensors and pump 
tubes from freezing. 

Rosette maintenance was performed on a regular basis. O-rings were changed as 
necessary and bottle maintenance was performed each day to insure proper 
closure and sealing. Valves were inspected for leaks and repaired or replaced 
as needed. 



4.3.  UNDERWATER ELECTRONICS PACKAGES  

CTD data were collected with a SBE9plus CTD (ODF #381). This instrument 
provided pressure, temperature, conductivity, dissolved O2, LSS and altimeter 
channels, and additionally measured a second PRT temperature and conductivity 
as a calibration check and backup. CTD #381 supplied a standard Sea-Bird 
format data stream at a data rate of 24 frames/second (fps). The CTD sensor 
configuration is provided in Table 4.2.0 in the previous section. 

The secondary CTD temperature and conductivity sensors were pumped separately 
from the primary sensors. They were mostly used as a calibration reference or 
to occasionally verify unusual T/S structures observed in the primary 
sensors. However, it was apparent after the cast that water was not being 
properly pumped past the primary sensors at the start of station 26, likely 
due to freezing problems discovered prior to station 27. The secondary sensor 
pair was used as the primary data source for station 26. 

The secondary conductivity sensor was not working properly during station 48. 
It was removed before station 49, then replaced before station 50 with a 
backup sensor belonging to the USCG. The primary conductivity sensor appeared 
to be consistent throughout the cruise, although Sea- Bird reported that it 
was broken and not able to be calibrated post-cruise. 

An SBE43 dissolved O2 sensor ducted to the same pump line as the primary CTD 
temperature and conductivity sensors. 

The CTD system was configured for single-conductor operation by combining 
together the 3 sea cable conductors. An SBE32 36-place carousel was the water 
sampler control unit on the rosette. An SBE11plus deck unit located in the 
Polar Star's main wet lab supplied power and telemetry control for the 
rosette water sampler and Sea-Bird CTD. The binary data were fed into the 
main CTD acquisition computer. Bottle-trip commands were sent from this 
computer to the SBE11 deck box, which transmitted the commands down the cable 
to the SBE32 water sampler unit. 



4.4.  NAVIGATION AND BATHYMETRY DATA ACQUISITION 

Navigation data were acquired from an ODF Garmin 128 GPS receiver via RS-232. 
Data were logged automatically at 2- to 10-second intervals by the Linux 
computer beginning August 28. These data were merged with Ashtech GPS data 
stored by the ship's computer systems from earlier in the leg, to fill in 
gaps from before the ODF navigation acquisition was up and running. 

Underway bathymetry was logged every 1-2 seconds by the ship's computer 
system, recording an uncorrected Knudsen echosounder depth. Depth data were 
not merged with ODF navigation data because of numerous erratic readings that 
might have distorted bottom profiles on vertical sections. However, the 
Knudsen data, eyeball-edited for repeatability, were used for start-, bottom- 
and end-of-cast bathymetry at each station. 



4.5.  CTD DATA ACQUISITION AND REAL-TIME CONTROL SYSTEM 

The CTD data acquisition and real-time control system consisted of a generic 
PC workstation running RedHat 7.3 Linux, an SBE-11plus deck unit and a VCR 
recorder for real-time analog backup recording of the sea-cable signal. The 
Linux system consisted of a color display with 3button trackball and keyboard 
(the CTD console), 10 RS-232 ports, 40-GB disk and CD-R drive. Two other 
Linux systems were networked to the data acquisition system, as well as to 
the rest of the networked computers aboard the Polar Star. These systems were 
available for real-time CTD data display and provided for CTD and 
hydrographic data management and backup. One HP 1200C/PS color inkjet printer 
provided hardcopy from any of the workstations. 

The data stream from the CTD was fed into the CTD acquisition computer 
through through a bidirectional serial line from the deck unit. This allowed 
bottle trips to be initiated and confirmed by the ODF data acquisition 
software. A bitmapped color display provided interactive graphical display 
and control of the CTD rosette sampling system, including real-time raw and 
processed CTD data, navigation, winch and rosette trip displays. 

The CTD data acquisition, processing and control system was prepared by the 
console watch a few minutes before each deployment. A console operations log 
was maintained for each deployment, containing a record of every attempt to 
trip a bottle as well as any pertinent comments. Most CTD console control 
functions, including starting the data acquisition, were initiated by 
pointing and clicking a trackball cursor on the display at icons representing 
functions to perform. The system then presented the operator with short 
dialog prompts with automatically-generated choices that could either be 
accepted as defaults or overridden. The operator was instructed to turn on 
the deck unit, then to examine a real-time CTD data display on the screen for 
stable data from the underwater unit. Once this was accomplished, the data 
acquisition and processing were begun and a time and position were 
automatically logged for the beginning of the cast. A backup analog recording 
of the CTD signal on a VCR tape was started at the same time as the data 
acquisition. A rosette trip display and pylon control window popped up, 
giving visual confirmation that the pylon was initializing properly. Various 
plots and displays were initiated. When all was ready, the console operator 
informed the deck watch by radio. 

Once the deck watch had deployed the rosette and informed the console 
operator that the rosette was at the surface (also confirmed by the computer 
displays), the console operator or watch leader provided the winch operator 
with a target depth (wire-out) and maximum lowering rate, normally 60 
meters/minute for this package. The package then began its descent, building 
up to the maximum rate during the first few hundred meters, then optimally 
continuing at a steady rate without any stops during the down cast. 

There were problems at the beginning of the leg with erratic winch speeds 
(frequent abrupt braking at higher speeds during lowering), caused by the 
automatic winch controller. These were resolved by using manual winch 
controls beginning with station 12. Adjustment of winch gearing also improved 
lowering rates. Another problem was excessive signal noise, which disappeared 
after re-wiring the sea cable away from the winch power source before station 
9, and by fixing a sea cable shield grounding problem prior to station 14. 

The console operator examined the processed CTD data during descent via 
interactive plot windows on the display, which could also be run at other 
workstations on the network. Additionally, the operator decided where to trip 
bottles on the up cast, noting this on the console log. The altimeter signal 
was also monitored for bottom proximity. 

Around 100-200 meters above the bottom, depending on bottom conditions, the 
altimeter typically began signaling a bottom return on the console. The winch 
speed was usually slowed to ~30 meters/minute during the bottom approach. The 
winch and altimeter displays allowed the watch leader to refine the target 
depth relayed to the winch operator and safely approach to within 10-20 
meters of the bottom. 

Bottles were closed on the up cast by pointing the console trackball cursor 
at a graphic firing control and clicking a button. The data acquisition 
system responded with the CTD rosette trip data and a pylon confirmation 
message in a window. All tripping attempts were noted on the console log. The 
console operator then instructed the winch operator to bring the rosette up 
to the next bottle depth. The console operator was also responsible for 
generating the sample log for the cast. 

After the last bottle was tripped, the console operator directed the deck 
watch to bring the rosette on deck. Once the rosette was on deck, the console 
operator terminated the data acquisition and turned off the deck unit and VCR 
recording. The VCR tape was filed. Usually the console operator also brought 
the sample log to the rosette room and served as the sample cop. 



4.6.  CTD DATA PROCESSING

ODF CTD processing software consists of over 30 programs running under the 
Linux operating system. The initial CTD processing program (ctdba) is used 
either in real-time or with existing raw data sets to: 

  •  Convert raw CTD scans into scaled engineering units, and assign the data 
     to logical channels 
  •  Filter various channels according to specified criteria 
  •  Apply sensor- or instrument-specific response-correction models 
  •  Decimate the channels according to specified criteria 
  •  Store the output time-series in a CTD-independent format 

Once the CTD data are reduced to a standard-format time-series, they can be 
manipulated in various ways. Channels can be additionally filtered. The time-
series can be split up into shorter time-series or pasted together to form 
longer time-series. A time-series can be transformed into a pressureseries, 
or into a larger-interval time-series. The pressure, temperature and 
conductivity laboratory calibration corrections are applied during the 
creation of the initial time- series. Oxygen corrections and any adjustments 
to the pressure, temperature or conductivity corrections for the series are 
maintained in separate files and are applied whenever the data are accessed. 

ODF data acquisition software acquired and processed the CTD data in 
realtime, providing calibrated, processed data for interactive plotting and 
reporting during a cast. The 24 fps data from the CTD were filtered, 
response-corrected and averaged to a 0.5-second time-series. Sensor 
correction and calibration models were applied to pressure, temperature, 
conductivity and O2. Rosette trip data were extracted from this timeseries in 
response to trip initiation and confirmation signals. The calibrated half-
second time-series data, as well as the 24 fps raw data, were stored on disk 
and were available in real-time for reporting and graphical display. At the 
end of the cast, various consistency and calibration checks were performed, 
and a 2-db pressure-series of the down cast was generated and subsequently 
used for reports and plots. 

CTD plots generated automatically at the completion of deployment were 
checked daily for potential problems. The two PRT temperature sensors were 
inter-calibrated and checked for sensor drift. The CTD conductivity sensor 
was monitored by comparing CTD values to check- sample conductivities, and by 
deep theta-salinity comparisons between down and up casts as well as adjacent 
stations. The CTD O2 sensor was calibrated to check-sample data. 

Some casts were subject to noise in the data stream caused by sea cable, 
slip-ring or deck unit problems (especially prior to station 14); or by 
moisture in interconnect cables between the CTD and external sensors (i.e. 
O2). Intermittent noisy data were filtered out of the half-second time- 
series data using a spike-removal filter. A least-squares polynomial of 
specified order was fit to fixed-length segments of data. Points exceeding a 
specified multiple of the residual standard deviation were replaced by the 
polynomial value. 

Density inversions can be induced in high-gradient regions by shipgenerated 
vertical motion of the rosette. Detailed examination of the raw data shows 
significant mixing can occur in these areas because of "ship roll". In order 
to minimize density inversions, a ship-roll filter was applied to all casts 
during pressure-sequencing to disallow pressure reversals. The pumps on the 
SBE9plus did not turn on until ~5 seconds after the CTD detected the in-water 
transition. The first few seconds of in-water data were excluded from the 
pressure-series data, since the sensors were still adjusting to the going-in-
water transition. 

Pressure intervals with no time-series data can optionally be filled by 
double-quadratic interpolation/extrapolation. The only pressure intervals 
missing/filled during this leg were at 0-4 db, caused by chopping off going-
in-water transition data during pressure-sequencing. 

There were two known casts with frozen sensor or pump-line problems at the 
start of the down casts, station 26 and station 47. Both were discovered 
after the cast was completed. The pump tubing was found frozen solid prior to 
station 27 and thawed prior to the cast, with no apparent damage to the 
sensors. Station 26 data showed some flow restriction at the start of the 
cast, so the secondary sensor pair was used for data processing. On station 
47, there were indications of flow restriction on the primary conductivity 
sensor going into the water, and the secondary sensor was emitting bad data. 
The secondary conductivity sensor was removed for station 48, and replaced by 
a backup sensor belonging to the USCG prior to station 49. 

When the down-cast CTD data have excessive noise, gaps or offsets, the upcast 
data are used instead. CTD data from down and up casts are not mixed together 
in the pressure-series data because they do not represent identical water 
columns (due to ship movement, wire angles, etc.). It was not necessary to 
use any up casts for Chukchi Borderland CTD data. 



4.7.  CTD LABORATORY CALIBRATION PROCEDURES  

Laboratory calibrations of the CTD pressure, temperature and conductivity 
sensors were used to generate Sea-Bird correction coefficients applied by the 
CTD data acquisition and processing software at sea. Pressure calibrations 
were last performed on CTD #381 at the ODF Calibration Facility (La Jolla) in 
May 2002, prior to Chukchi Borderland. The Paroscientific Digiquartz pressure 
transducer (s/n 58952) was calibrated in a temperature-controlled water bath 
to a Ruska Model 2400 Piston Gauge pressure reference. Calibration curves 
were measured at 5 temperatures from -2.06 to 32.36 deg.C to four maximum 
loading pressures (2086, 2774, 3463 and 2x6079 decibars). The SBE3plus 
sensors (primary/PRT1 s/n 03-2505, secondary/PRT2 s/n 03-2380) were 
calibrated to a NBIS ATB-1250 resistance bridge and Rosemount standard PRT. 
The SBE4 conductivity sensors (primary/C1 s/n 04-1919 and secondary/C2 s/n 
04-2023) were calibrated in May 2002 at Sea-Bird Electronics. The C2 sensor 
was removed after station 48 because of damage from freezing. It was replaced 
by s/n 04-1549, owned by the USCG, from station 50 until the end of the 
expedition. This sensor was also calibrated in May 2002 and was used as the 
secondary conductivity on the preceding leg (AWS-02-I). After applying the 
pre-cruise calibration coefficients, CTD pressure, temperature and 
conductivity data were within +/-0.2 decibars, +/-0.0002 deg.C and +/-0.0005 
mS/cm, respectively, compared to laboratory standard values. 

Pressure and temperature calibration procedures were repeated post-cruise at 
ODF. Preliminary results indicate a pre- to post-cruise temperature 
difference of +/-0.0002 deg.C over the temperature ranges seen during the 
cruise. Post-cruise conductivity calibrations were carried out by SeaBird; 
the cell on the primary sensor was broken when it arrived at Sea-Bird and 
could not be calibrated until after repairs were made. Shipboard comparisons 
of CTD and bottle conductivities (see next section) indicate no problems with 
the primary sensor during the cruise. But the primary sensor data will be 
more closely compared to the secondary sensors for possible malfunctions 
before CTD salinity data are considered final. 



4.8.  CTD SHIPBOARD CALIBRATION PROCEDURES

ODF SBE-CTD #381 was used for all Chukchi Borderland casts. A redundant PRT 
sensor was used on CTD #381 as a calibration check while at sea. CTD 
conductivity and dissolved O2 were calibrated to in-situ check samples 
collected during each rosette cast. 

4.8.1.  CTD #381 Pressure 

Pre-cruise pressure calibration coefficients were applied to CTD #381 raw 
pressures during each cast. No additional adjustments were made to the 
calculated pressures. Residual offsets at the beginning and end of each cast 
(the difference between the first/last pressures in-water and 0) were 
monitored during the cruise to check for shifts in the pressure calibration. 
Almost all residual differences were 0.5 decibar or less; only 8 going-in 
pressures were between 0.5 and 1.0 decibar off. There was no apparent shift 
in pressure calibration during the cruise. 

CTD pressure data will not be considered final until after the post-cruise 
laboratory calibrations have been completed and analyzed. Preliminary results 
of the post-cruise pressure calibration indicate a correction change of -0.3 
to +0.1 decibar for the pressure and temperature ranges seen during this 
cruise. 

4.8.2.  CTD #381 Temperature 

Pre-cruise laboratory calibration coefficients for the CTD #381 primary and 
secondary temperature sensors (PRT1 and PRT2) were applied to all shipboard 
CTD data. The two temperature channels were compared on all casts to monitor 
for drift. Preliminary corrected temperatures were compared for a series of 
standard depths from each CTD down-cast. Comparison of the two CTD #381 PRTs 
every 200 decibars at down-cast pressures 500 decibars and deeper showed the 
difference to be very stable during the cruise. Figure 4.8.2.0 summarizes the 
shipboard comparison between the primary and secondary PRT channels for CTD 
#381. 


Figure 4.8.2.0: Shipboard comparison of CTD #381 dual PRTs, PRT1-PRT2, 
                pressure>500db. 


CTD temperature data will not be considered final until after the post-cruise 
laboratory calibrations have been completed and analyzed. Preliminary results 
indicate a change of less than +/-0.0003 deg.C for temperatures in the range 
of this cruise. 

4.8.3.  CTD #381 Conductivity 

Sea-Bird pre-cruise conductivity calibration coefficients were applied to 
primary and secondary conductivity sensors during each CTD cast. Corrected 
CTD rosette trip pressures and temperatures were used with bottle salinities 
to calculate bottle conductivities. Differences between the bottle and CTD 
conductivities were then used to derive a shipboard conductivity correction. 
The conductivity range and slope were both small, so it was decided to defer 
any slope correction until after station offsets were determined. 

Bottle-CTD conductivity differences were biased on the high side in the 
thermocline. After closely analyzing a few CTD casts, it was determined that 
water dragged by the rosette and lack of motion by the ship (mostly in ice) 
prevented proper flushing of bottles and mis-matches of bottle and CTD data 
in high-gradient areas. Two flushing tests were done: on station 57, tripping 
2 sets of 3 thermocline bottles 20 seconds, 1 minute and 2 minutes after 
stopping; and on station 61, tripping 2 sets of 2 thermocline bottles 20 
seconds after stopping and after moving the rosette 2m up, 4m down and 2m up 
at the same level. Either the bottle differences were essentially the same, 
or they were the opposite sign and still large differences, in 4 out of 5 
tests; so bottle sampling techniques were not modified. Instead, CTD 
conductivity offset values were calculated for all stations deep enough, 
using only bottle conductivities deeper than 500 db. Figure 4.8.3.0 
illustrates the Chukchi Borderland preliminary shipboard conductivity offset 
values. 


Figure 4.8.3.0: Chukchi Borderland CTD #381 preliminary shipboard 
                conductivity offsets by station number.


Smoothed offsets were applied to each cast. Then conductivity differences 
above and below the thermocline were fit to CTD conductivity for all stations 
to determine a shipboard conductivity slope. A first-order fit was 
calculated, with outlying values (4,2 standard deviations) rejected. Figure 
4.8.3.1 shows the data used to determine the Chukchi Borderland preliminary 
conductivity slope.


Figure 4.8.3.1: Chukchi Borderland CTD #381 preliminary shipboard 
                conductivity slope.


Some offsets were manually adjusted to account for discontinuous shifts in 
the conductivity transducer response or bottle salinities, or to maintain 
deep theta-salinity consistency from cast to cast. Cast-by-cast comparisons 
showed minimal drifts in conductivity offset (less than 0.001 mS/cm), except 
between stations 25-30. The larger drift (~ 0.003 mS/cm total) in this area 
was attributed to frozen sensors at the start of stations 26 and 27. There 
were no apparent slope changes over the entire leg. 

The standard salinity batch was changed from P-140 to P-136 beginning station 
98 through the end of the cruise, due to a shortage of P-140 onboard. 
Although the two batches were inter- calibrated on-board and showed a small 
difference, the preliminary CTD theta-salinity comparisons did not warrant an 
additional offset based on batch differences. No adjustments to corrections 
were made for the standard batch change. 


The final shipboard Chukchi Borderland conductivity slopes are summarized in 
Figure 4.8.3.2. Figure 4.8.3.3 summarizes the final shipboard conductivity 
offsets. 


Figure 4.8.3.2: Chukchi Borderland CTD #381 shipboard conductivity slope 
                correction by station number.
Figure 4.8.3.3: Chukchi Borderland CTD #381 shipboard conductivity offsets 
                by station number. Summary of Residual Salinity Differences


Figures 4.8.3.4, 4.8.3.5 and 4.8.3.6 summarize the Chukchi Borderland 
differences between bottle and CTD salinities after applying the shipboard 
conductivity corrections. Only CTD and bottle salinities with quality code 2 
(acceptable) were used to generate these figures and statistics. Residual 
differences exceeding +/-0.025 PSU are included in the calculations for 
averages and standard deviations, even though they are not plotted. The 
large/high thermocline differences from lack of proper bottle flushing are 
evident on the first two plots, which include all data,


Figure 4.8.3.4: Salinity residual differences vs pressure (after 
                correction).
Figure 4.8.3.5: Salinity residual differences vs station # (after 
                correction).
Figure 4.8.3.6: Deep salinity residual differences vs station # (after 
                correction).


The CTD conductivity calibration represents a best estimate of the 
conductivity field throughout the water column. 3-sigma from the mean 
residual in Figures 4.8.3.5 and 4.8.3.6, or +/-0.0807 PSU for all salinities 
and +/-0.0024 PSU for deep salinities, represents the limit of repeatability 
of the bottle salinities (Autosal, rosette, operators and samplers). This 
limit agrees with station overlays of deep theta-salinity. Within most casts 
(a single salinometer run), the precision of bottle salinities appears to be 
better than 0.001 PSU. The precision of the CTD salinities appears to be 
better than 0.0005 PSU. 

Tabulation of pressure, temperature and conductivity correction coefficients 
and historical data comparisons will be included in the final Chukchi 
Borderland report, after corrections are finalized. 

4.8.4.  CTD Dissolved Oxygen 

A single pumped SBE43 dissolved O2 sensor was used for the entire cruise. 

There were a number of problems with the response characteristics of 
SensorMedics O2 sensors typically used with NBIS MKIII CTDs, the major ones 
being a secondary thermal response and a sensitivity to profiling velocity. 
Stopping the rosette for as little as half a minute, or slowing down for a 
bottom approach, could cause shifts in the CTD O2 profile as oxygen became 
depleted in water near the sensor. This was still an apparent problem on the 
Nordic Seas cruise in Summer 2002, despite using an SBE43 pumped sensor with 
an NBIS MKIII CTD. 

This was the first time the pumped SBE43 sensor was used with a SBE9plus CTD 
by ODF with its Unix/Linux acquisition system. The typical profiling velocity 
problems seen with the non- pumped SensorMedics O2 sensors, paired with NBIS 
Mark III CTDs, were still somewhat apparent, but at a much smaller magnitude. 

Raw oxygen data were offset when it was apparent that the signal shifted due 
to slowdowns for a bottom approach; all deep shifts were less than 0.2 
percent. Surface mixed-layer oxygen data were often affected by the goingin-
water transition on most casts; raw surface oxygens were offset to a match a 
deeper mixed-layer value below this transition area to help the surface fits 
match the bottles better. Any changed data levels are coded as "despiked" 
(code 7) in the data files (see Bottle Data Processing section). 

Because of the signal-drop problems still evident with the SBE43 during 
package stops or slowdowns, up-cast CTD rosette trip data cannot be optimally 
calibrated to O2 check samples. Instead, down-cast CTD O2 data are derived by 
matching the up-cast rosette trips along isopycnal surfaces. The differences 
between CTD O2 data modeled from these derived values and check samples are 
then minimized using a non-linear least-squares fitting procedure. 

The down- and up-cast time-series oxygen profiles are fairly similar when 
viewed using the corrections generated during the pressure-series fits, not 
typical of the Sensormedics sensors previously used. However, down-cast 
extrema in higher-gradient areas of the top 1000 decibars are often 10-20 
meters deeper than the same features on the up-cast, as with the Sensormedics 
sensors. This is probably due to a combination of water being dragged by the 
rosette and slow sensor response not accounted for by lags. 

Figures 4.8.4.0 and 4.8.4.1 show the residual differences between the 
corrected CTD O2 and the bottle O2 (ml/l) for each station. Only CTD and 
bottle oxygens with quality code 2 (acceptable) were used to generate these 
figures and statistics. Residual differences exceeding +/-0.5 ml/l are 
included in the calculations for averages and standard deviations, even 
though they are not plotted.


Figure 4.8.4.0: Chukchi Borderland O2 residual differences vs station # 
                (after prelim. correction). 
Figure 4.8.4.1: Chukchi Borderland Deep O2 residual differences vs station 
                # (after prelim. correction). 


The standard deviations of 0.184 ml/l for all oxygens and 0.013 ml/l for deep 
oxygens are only intended as indicators of how well the up-cast bottle and 
down-cast CTD O2 values match up. ODF makes no claims regarding the precision 
or accuracy of CTD dissolved O2 data. As with other CTD properties, the CTD 
dissolved O2 data are not considered final until after post-cruise pressure 
and temperature calibrations have been completed and analyzed. 

The general form of the ODF O2 conversion equation follows Brown and Morrison 
[Brow78] and Millard [Mill82], [Owen85]. ODF does not use a digitized O2 
sensor temperature to model the secondary thermal response but instead models 
membrane and sensor temperatures by low- pass filtering the PRT temperature. 
Insitu pressure and temperature are filtered to match the sensor response. 
Time-constants for the pressure response Taup, and two temperature responses 
TauTs and TauTf are fitting parameters. The Oc gradient, dOc/dt, is 
approximated by low-pass filtering 1st-order Oc differences. This gradient 
term attempts to correct for reduction of species other than O2 at the 
cathode. The time-constant for this filter, Tauog, is a fitting parameter. 
Oxygen partial-pressure is then calculated: 


    Opp=[c1*Oc+c2]*fsat(S,T,P)*e**(c3*Pl+c4*Tf+c5*Ts+c6*dOc/dt)     (4.8.4.0)


          Opp  =  Dissolved O2 partial-pressure in atmospheres (atm); 
           Oc  =  Sensor current (uamps); 
  fsat(S,T,P)  =  O2 saturation partial-pressure at S,T,P (atm); 
            S  =  Salinity at O2 response-time (PSUs); 
            T  =  Temperature at O2 response-time (deg.C); 
            P  =  Pressure at O2 response-time (decibars); 
           Pl  =  Low-pass filtered pressure (decibars); 
           Tf  =  Fast low-pass filtered temperature (deg.C); 
           Ts  =  Slow low-pass filtered temperature (deg.C); 
       dOc/dt  =  Sensor current gradient (uamps/secs). 


Tabulation of oxygen correction coefficients will be included in the final 
Chukchi Borderland report, after corrections are finalized.

4.8.5.  CTD Quality Codes 

Preliminary quality coding of Chukchi Borderland CTD data was done using a 
coding scheme developed for the World Ocean Circulation Experiment (WOCE) 
Hydrographic Programme (WHP). WHP CTD quality codes were assigned as defined 
in the WOCE Operations Manual [Joyc94] with the following interpretations: 


  2  Acceptable measurement. 
  3  Questionable measurement. Typically, there were problems with noise, 
      calibration, pumps, etc., which made the data suspect. 
  6  Extrapolated/Interpolated data. Missing levels filled by double-
     quadratic interpolation/extrapolation of adjacent data. 
  7  Despiked. The CTD data have been filtered to eliminate a spike or 
     offset. Explanations of CTD data coded "3", or any large segments of 
     data coded "7", will be included with the final documentation. 



5.  BOTTLE SAMPLING 

At the end of each rosette deployment water samples were drawn from the 
bottles in the following order: 

  •  CFCs 
  •  He-3 
  •  O2 

The remaining water samples were drawn in arbitrary order: 

  •  Ba 
  •  O-18 
  •  Nutrients 
  •  I-129 
  •  Salinity 

Note that some properties were subsampled by cast or by station, so the 
actual sequence of samples drawn was modified accordingly. Not all sample 
types were drawn at each station. Some stations had several additional 
bottles tripped just for Cs-137 or N:Ar samples. Salinity check samples were 
drawn after sampling Cs-137, and O2 check samples were drawn before and after 
each N:Ar sample. 

The correspondence between individual sample containers and the rosette 
bottle from which the sample was drawn was recorded on the sample log for the 
cast. This log also included any comments or anomalous conditions noted about 
the rosette and bottles. One member of the sampling team was designated the 
sample cop, whose sole responsibility was to maintain this log and insure 
that sampling progressed in the proper drawing order. 

Normal sampling practice included opening the drain valve and then the air 
vent on the bottle, indicating an air leak if water escaped. This observation 
together with other diagnostic comments (e.g., "lanyard caught in lid", 
"valve left open") that might later prove useful in determining sample 
integrity were routinely noted on the sample log. Drawing oxygen samples also 
involved taking the sample draw temperature from the bottle. The temperature 
was noted on the sample log and was sometimes useful in determining leaking 
or mis-tripped bottles. 

Once individual samples had been drawn and properly prepared, they were 
distributed to their respective laboratories for analysis. Oxygen, nutrients 
and salinity analyses were performed on computer-assisted (PC) analytical 
equipment networked to the data processing computer for centralized data 
analysis. The analysts for each specific property were responsible for 
insuring that their results were updated into the cruise database.



5.1  BOTTLE DATA PROCESSING

Bottle data processing began with sample drawing, and continued until the 
data were considered to be final. One of the most important pieces of 
information, the sample log sheet, was filled out during the drawing of the 
many different samples. It was useful both as a sample inventory and as a 
guide for the technicians in carrying out their analyses. Any problems 
observed with the rosette before or during the sample drawing were noted on 
this form, including indications of bottle leaks, out-of-order drawing, etc. 
Additional clues regarding bottle tripping or leak problems were found by 
individual analysts as the samples were analyzed and the resulting data were 
processed and checked by those personnel. 

The next stage of processing was accomplished after the individual parameter 
files were merged into a common station file, along with CTDderived 
parameters (pressure, temperature, conductivity, etc.). The rosette cast and 
bottle numbers were the primary identification for all ODF-analyzed samples 
taken from the bottle, and were used to merge the analytical results with the 
CTD data associated with the bottle. At this stage, bottle tripping problems 
were usually resolved, sometimes resulting in changes to the pressure, 
temperature and other CTD properties associated with the bottle. All CTD 
information from each bottle trip (confirmed or not) was retained in a file, 
so resolving bottle tripping problems consisted of correlating CTD trip data 
with the rosette bottles. 

Diagnostic comments from the sample log, and notes from analysts and/or 
bottle data processors were entered into a computer file associated with each 
station (the "quality" file) as part of the quality control procedure. Sample 
data from bottles suspected of leaking were checked to see if the properties 
were consistent with the profile for the cast, with adjacent stations, and, 
where applicable, with the CTD data. Various propertyproperty plots and 
vertical sections were examined for both consistency within a cast and 
consistency with adjacent stations by data processors, who advised analysts 
of possible errors or irregularities. The analysts reviewed and sometimes 
revised their data as additional calibration or diagnostic results became 
available. 

Quality coding of CTD and water samples was done using a coding scheme 
developed for the World Ocean Circulation Experiment (WOCE) Hydrographic 
Programme (WHP) [Joyc94]. Based on the outcome of investigations of the 
various comments in the quality files, WHP water sample codes were selected 
to indicate the reliability of the individual parameters affected by the 
comments. WHP bottle codes were assigned where evidence showed the entire 
bottle was affected, as in the case of a leak, or a bottle trip at other than 
the intended depth. 

WHP water bottle quality codes were assigned as defined in the WOCE 
Operations Manual [Joyc94] with the following additional interpretations: 

  2  No problems noted. 
  3  Leaking. An air leak large enough to produce an observable effect on a 
     sample is identified by a code of 3 on the bottle and a code of 4 on the 
     oxygen. (Small air leaks may have no observable effect, or may only 
     affect gas samples.) 
  4  Did not trip correctly. Bottles tripped at other than the intended depth 
     were assigned a code of 4. There may be no problems with the associated 
     water sample data. 
  5  Not reported. No water sample data reported. This is a representative 
     level derived from the CTD data for reporting purposes. The sample 
     number should be in the range of 80-99. 
  9  The samples were not drawn from this bottle. 


WHP water sample quality flags were assigned using the following criteria:

  1  The sample for this measurement was drawn from the water bottle, but the 
     results of the analysis were not (yet) received. 
  2  Acceptable measurement. 
  3  Questionable measurement. The data did not fit the station profile or 
     adjacent station comparisons (or possibly CTD data comparisons). No 
     notes from the analyst indicated a problem. The data could be 
     acceptable, but are open to interpretation. 
  4  Bad measurement. The data did not fit the station profile, adjacent 
     stations or CTD data. There were analytical notes indicating a problem, 
     but data values were reported. Sampling and analytical errors were also 
     coded as 4. 
  5  Not reported. There should always be a reason associated with a code of 
     5, usually that the sample was lost, contaminated or rendered unusable. 
  9  The sample for this measurement was not drawn. 


WHP water sample quality flags were assigned to the CTDSAL (CTD salinity) 
parameter as follows:

  2  Acceptable measurement. 
  3  Questionable measurement. The data did not fit the bottle data, or there 
     was a CTD conductivity calibration shift during the up-cast. 
  4  Bad measurement. The CTD up-cast data were determined to be unusable for 
     calculating a salinity. 
  7  Despiked. The CTD data have been filtered to eliminate a spike or 
     offset. 


Note that CTDOXY values were derived from the down-cast pressure-series CTD 
data. CTD data were matched to the up-cast bottle data along isopycnal 
surfaces. If the CTD salinity is footnoted as bad or questionable, the CTD O2 
is not reported. CTDOXY quality codes in the bottle files have not been 
modified from the default "Acceptable/Code 2" for the preliminary data set.

Table 5.0 shows the number of samples drawn and the number of times each WHP 
sample quality flag was assigned for each basic hydrographic property. 
Nutrient data are temporarily omitted from this chart until they can be 
incorporated into the ODF bottle data files. 


Table 5.0: Frequency of WHP quality flag assignments for Chukchi Borderland. 

                 _______________________________________________

                          Rosette Samples Stations 001-126
                 -----------------------------------------------
                               WHP   Quality Codes
                 Reported Levels | 1  2     3   4   5      7  9
                 Bottle    3206  | 0  3162  17  14  0     0  13
                 CTD Salt  3206  | 0  3206  0   0   0     0  0
                 CTD Oxy   3206  | 0  3206  0   0   0     0  0
                 Salinity  3038  | 0  3017  20  1   0     0  168
                 Oxygen    2928  | 0  2922  5   1   2     0  276
                 _______________________________________________


5.1.1  Bottle Pressure and Temperature 

All pressures and temperatures for the bottle data tabulations on the rosette 
casts were obtained by averaging CTD data for a brief interval at the time 
the bottle was closed on the rosette, then correcting the data based on CTD 
laboratory calibrations. The temperatures are reported using the 
International Temperature Scale of 1990. 

5.1.2  Salinity Analysis 

Equipment and Techniques 

A single Guildline Autosal Model 8400A salinometer (s/n 57-396), located in 
the main wet lab, was used for measuring salinity on all stations. The 
salinometer was modified by ODF to contain an interface for computer-aided 
measurement. The water bath temperature was set and maintained at a value 
near the laboratory air temperature. It was set at 24 deg.C for the entire 
leg. 

The salinity analyses were performed when samples had equilibrated to 
laboratory temperature, usually within 16-36 hours after collection. 
Equilibration time was sometimes accelerated by blowing warm air on sample 
boxes with a fan and heater because of the extreme differences between in 
situ sample temperatures and the lab temperature. The salinometer was 
standardized for each group of analyses (usually one or two casts, up to ~60 
samples) using at least one fresh vial of standard seawater per group. One 
group included 107 samples and 4 casts between standardizations. A computer 
(PC) prompted the analyst for control functions such as changing sample, 
flushing, or switching to "read" mode. The salinometer cell was flushed and 
results were logged by the computer until two successive measurements met 
software criteria for consistency. These values were then averaged for a 
final result. 

Sampling and Data Processing 

Salinity samples were drawn into 200 ml Kimax high-alumina borosilicate 
bottles, which were rinsed three times with sample prior to filling. The 
bottles were sealed with custom-made plastic insert thimbles and Nalgene 
screw caps. This assembly provides very low container dissolution and sample 
evaporation. Prior to collecting each sample, inserts were inspected for 
proper fit and loose inserts were replaced to insure an airtight seal. The 
draw time and equilibration time were logged for all casts. Laboratory 
temperatures were logged at the beginning and end of each run. 

PSS-78 salinity [UNES81] was calculated for each sample from the measured 
conductivity ratios. The difference (if any) between the initial vial of 
standard water and one run at the end as an unknown was applied linearly to 
the data to account for any drift. The data were added to the cruise 
database. 3038 salinity measurements were made and approximately 172 vials of 
standard water were used. 18 replicate samples were also measured to test the 
spare salinometer or to compare standard batches. The estimated accuracy of 
bottle salinities run at sea is usually better than 0.002 PSU relative to the 
particular standard seawater batch used. 

Laboratory Temperature 

The temperature in the salinometer laboratory varied from 22 to 25.3 deg.C, 
within 2 deg.C of the bath temperature, during the cruise. The air 
temperature change during a run of samples was less than +/-1.2 deg.C. 

Standards 

IAPSO Standard Seawater (SSW) Batch P-140 (148 vials) was used to standardize 
the salinometer for stations 1-97. Batch P-136 (24 vials) was used for 
stations 98-126, after the P140 standard was depleted. A few replicate 
samples from station 76 were run with the P-136 standard 4 days after the 
original samples were run with P-140. The bottle salinities from the 
replicate samples were consistently 0.001-0.002 PSU lower than the originals, 
indicating the P136 standard could be high compared to its label (or the P-
140 low compared to its label). 

5.1.3.  Oxygen Analysis 

Equipment and Techniques 

Dissolved oxygen analyses were performed with an ODF-designed automated 
oxygen titrator using photometric end-point detection based on the absorption 
of 365nm wavelength ultra-violet light. The titration of the samples and the 
data logging were controlled by PC software. Thiosulfate was dispensed by a 
Dosimat 665 buret driver fitted with a 1.0 ml buret. 

ODF used a whole-bottle modified-Winkler titration following the technique of 
Carpenter [Carp65] with modifications by Culberson et al. [Culb91], but with 
higher concentrations of potassium iodate standard (~0.012N) and thiosulfate 
solution (~65 gm/l). Pre-made liquid potassium iodate standards were run at 
the beginning of each session of analyses, which typically included from 1 to 
3 stations. Reagent/distilled water blanks were determined, to account for 
presence of oxidizing or reducing materials. The auto-titrator generally 
performed very well. 

Sampling and Data Processing 

Samples were collected for dissolved oxygen analyses soon after the rosette 
sampler was brought on board. Using a Tygon drawing tube, nominal 125ml 
volume-calibrated iodine flasks were rinsed 2-3 times with minimal agitation, 
then filled and allowed to overflow for at least 3 flask volumes. The sample 
draw temperature was measured with a small platinum resistance thermometer 
embedded in the drawing tube. Reagents were added to fix the oxygen before 
stoppering. The flasks were shaken twice to assure thorough dispersion of the 
precipitate, once immediately after drawing, and then again after about 20 
minutes. 

The thermometer used to measure draw temperature began to misbehave around 
station 96, and was replaced at station 105. The replacement did not work 
properly, either, so sample draw temperatures were not taken for stations 96 
or 106-126. 

The samples were analyzed within 1-6 hours of collection, then the data were 
merged into the cruise database. 

Thiosulfate normalities were calculated from each standardization and 
corrected to 20 deg.C. The 20 deg.C normalities and the blanks were plotted 
versus time and were reviewed for possible problems. New thiosulfate 
normalities will be recalculated after the blanks have been smoothed as a 
function of time, if warranted. These new normalities will then be smoothed, 
and the oxygen data recalculated. 

As samples warmed up to room temperature they would often degas which would 
cause an occasional noisy endpoint due to gas bubbles in the light path. 2928 
oxygen measurements were made, with no major problems with the analyses. In 
addition, 22 oxygen samples from post-N:Ar sampling and 26 random replicate 
samples were also analyzed but not reported with the ODF data. 

Volumetric Calibration 

Oxygen flask volumes were determined gravimetrically with degassed deionized 
water to determine flask volumes at ODF's chemistry laboratory. This is done 
once before using flasks for the first time and periodically thereafter when 
a suspect bottle volume is detected. The volumetric flasks used in preparing 
standards were volume-calibrated by the same method, as was the 10 ml Dosimat 
buret used to dispense standard iodate solution. 

Standards 

Liquid potassium iodate standards were prepared and bottled in ODF's 
chemistry laboratory prior to the cruise. The normality of the liquid 
standard was determined at ODF by calculation from weight. Two different 
standard batches used during the cruise agreed well. Potassium iodate was 
obtained from Acros Chemical Co. and was reported by the supplier to be 
>99.4% pure. All other reagents were "reagent grade" and were tested for 
levels of oxidizing and reducing impurities prior to use. 

5.1.4.  Nutrient Analysis 

Equipment and Techniques 

Nutrient analyses (phosphate, silicate, nitrate and nitrite) were performed 
on an ODF-modified 4-channel Technicon AutoAnalyzer II, generally within one 
hour after sample collection. Occasionally samples were refrigerated up to 10 
hours at ~4 deg.C. All samples were brought to room temperature prior to 
analysis. 

The methods used are described by Gordon et al. [Gord92]. The analog outputs 
from each of the four colorimeter channels were digitized and logged 
automatically by computer (PC) at 2second intervals. 

Silicate was analyzed using the technique of Armstrong et al. [Arms67]. An 
acidic solution of ammonium molybdate was added to a seawater sample to 
produce silicomolybdic acid which was then reduced to silicomolybdous acid (a 
blue compound) following the addition of stannous chloride. Tartaric acid was 
also added to impede PO4 color development. The sample was passed through a 
15mm flowcell and the absorbance measured at 660nm. 

A modification of the Armstrong et al. [Arms67] procedure was used for the 
analysis of nitrate and nitrite. For the nitrate analysis, the seawater 
sample was passed through a cadmium reduction column where nitrate was 
quantitatively reduced to nitrite. Sulfanilamide was introduced to the sample 
stream followed by N-(1-naphthyl)ethylenediamine dihydrochloride which 
coupled to form a red azo dye. The stream was then passed through a 15mm 
flowcell and the absorbance measured at 540nm. The same technique was 
employed for nitrite analysis, except the cadmium column was bypassed, and a 
50mm flowcell was used for measurement. 

Phosphate was analyzed using a modification of the Bernhardt and Wilhelms 
[Bern67] technique. An acidic solution of ammonium molybdate was added to the 
sample to produce phosphomolybdic acid, then reduced to phosphomolybdous acid 
(a blue compound) following the addition of dihydrazine sulfate. The reaction 
product was heated to ~55 deg.C to enhance color development, then passed 
through a 50mm flowcell and the absorbance measured at 820nm. 

Sampling and Data Processing 

Nutrient samples were drawn into 45 ml polypropylene, screw-capped "oakridge 
type" centrifuge tubes. The tubes were cleaned with 10% HCl and rinsed with 
sample 2-3 times before filling. Standardizations were performed at the 
beginning and end of each group of analyses (typically one cast, up to 36 
samples) with an intermediate concentration mixed nutrient standard prepared 
prior to each run from a secondary standard in a lownutrient seawater matrix. 
The secondary standards were prepared aboard ship by dilution from primary 
standard solutions. Dry standards were preweighed at the laboratory at ODF, 
and transported to the vessel for dilution to the primary standard. Sets of 
6-7 different standard concentrations were analyzed periodically to determine 
any deviation from linearity as a function of concentration for each nutrient 
analysis. A correction for non-linearity was applied to the final nutrient 
concentrations when necessary. 

After each group of samples was analyzed, the raw data file was processed to 
produce another file of response factors, baseline values, and absorbances. 
Computer-produced absorbance readings were checked for accuracy against 
values taken from a strip chart recording. The data were then added to the 
cruise database. 

Nutrients, reported in micromoles per kilogram, were converted from 
micromoles per liter by dividing by sample density calculated at 1 atm 
pressure (0 db), in situ salinity, and an assumed laboratory temperature of 
25 deg.C. 

2662 nutrient samples were analyzed. The pump tubing was changed 1 time, 
before analyzing station 65 samples. Silicate molybdate pump tubing was 
replaced again before analyzing station 95. 

Standards 

Primary standards for silicate (Na2SiF6), nitrate (KNO3), nitrite (NaNO2) and 
phosphate (KH2PO4) were obtained from Johnson Matthey Chemical Co.; the 
supplier reported purities of >98%, 99.999%, 97% and 99.999%, respectively. 
The efficiency of the cadmium column used for nitrate was monitored 
throughout the cruise and ranged from 99-100%. 

No major problems were encountered with the measurements. The temperature of 
the laboratory used for the analyses ranged from 22 deg.C to 25.5 deg.C, but 
was relatively constant during any one station (+/-1.5 deg.C). 


References 

Arms67. 
Armstrong, F. A. J., Stearns, C. R., and Strickland, J. D. H., "The 
measurement of upwelling and subsequent biological processes by means of 
the Technicon Autoanalyzer and associated equipment," Deep-Sea Research, 
14, pp. 381-389 (1967). 

Bern67. 
Bernhardt, H. and Wilhelms, A., "The continuous determination of low level 
iron, soluble phosphate and total phosphate with the AutoAnalyzer," 
Technicon Symposia, I, pp. 385-389 (1967). 

Brow78. 
Brown, N. L. and Morrison, G. K., "WHOI/Brown conductivity, temperature and 
depth microprofiler," Technical Report No. 78-23, Woods Hole Oceanographic 
Institution (1978). 

Carp65. 
Carpenter, J. H., "The Chesapeake Bay Institute technique for the Winkler 
dissolved oxygen method," Limnology and Oceanography, 10, pp. 141-143 
(1965). 

Culb91. 
Culberson, C. H., Knapp, G., Stalcup, M., Williams, R. T., and Zemlyak, F., 
"A comparison of methods for the determination of dissolved oxygen in 
seawater," Report WHPO 91-2, WOCE Hydrographic Programme Office (Aug 
1991). 

Gord92. 
Gordon, L. I., Jennings, J. C., Jr., Ross, A. A., and Krest, J. M., "A 
suggested Protocol for Continuous Flow Automated Analysis of Seawater 
Nutrients in the WOCE Hydrographic Program and the Joint Global Ocean 
Fluxes Study," Grp. Tech Rpt 92-1, OSU College of Oceanography Descr. Chem 
Oc. (1992). 

Joyc94. 
Joyce, T., ed. and Corry, C., ed., "Requirements for WOCE Hydrographic 
Programme Data Reporting," Report WHPO 90-1, WOCE Report No. 67/91, pp. 
52-55, WOCE Hydrographic Programme Office, Woods Hole, MA, USA (May 1994, 
Rev. 2). UNPUBLISHED MANUSCRIPT. 

Mill82. 
Millard, R. C., Jr., "CTD calibration and data processing techniques at WHOI 
using the practical salinity scale," Proc. Int. STD Conference and 
Workshop, p. 19, Mar. Tech. Soc., La Jolla, Ca. (1982). 

Owen85. 
Owens, W. B. and Millard, R. C., Jr., "A new algorithm for CTD oxygen 
calibration," Journ. of Am. Meteorological Soc., 15, p. 621 (1985). 

UNES81. 
UNESCO, "Background papers and supporting data on the Practical Salinity 
Scale, 1978," UNESCO Technical Papers in Marine Science, No. 37, p. 144 
(1981).  • 

(End of EXTRACT from ODF Preliminary Cruise Report)



6.  CFC MEASUREMENTS PROGRAM 
    (Eugene Gorman, Guy Mathieu, Sarah Zimmermann, Kevin Vranes, Bill 
    Smethie) 

Methods 

Water samples were collected in 10-l Bullister style rosette bottles. CFC 
samples -the first samples taken from the bottles -were drawn into 100-cc 
precision ground glass syringes and stored in a sink filled with clean 
surface seawater until analysis. Samples were stored for no longer than 8 
hours. Air samples were collected by pumping air from the bow directly to the 
CFC analysis system during periods when the bow was into the wind. 

The CFC samples were analyzed using an automated purge and trap system 
interfaced to a gas chromatograph with an electron capture detector for CFCs 
11, 12, and 113. The column arrangement for the gas chromatograph consisted 
of a 3 foot x 1/8 inch diameter precolumn of Porasil-B, a 5 foot x 1/8 inch 
diameter main column of Carbograph 1ac and a 4 inch x 1/8 inch diameter post 
column of molecular sieve 5A. The precolumn and main column were operated at 
95°C and the post column at 40°C. The post column separated N2O from CFC-12 
and was valved out of the gas stream before CFC-11 and CFC-113 eluted. The 
precolumn and main column provided good separation between the CFCs and 
methyl iodide. Chromatograms were acquired digitally on a PC and the CFC peak 
areas determined using HP Chemstation software. 

Calibration curves were run at the beginning and end of the cruise and every 
3-4 days in between. A gas standard with known amounts of CFCs 11, 12 and 113 
in nitrogen in seawater ratios was used for calibration. This standard was 
prepared about 4 months prior to the cruise and since we had no history on 
its stability, it was calibrated several times during the course of the 
cruise against a standard kindly provided to us by John Bullister of 
PMEL/NOAA. From our initial analysis of these results, our standard appeared 
to be stable and a more careful analysis of these results will be carried out 
after the cruise. The standards are on the SIO 98 calibration scale. 

Two CFC analysis systems were used. Duplicates were collected nearly every 
station for comparison of the two systems and for determination of the 
precision for each system. Preliminary calibration curves were fit to the 
calibration data and preliminary CFC concentrations calculated after the 
completion of each station. These preliminary data were merged with the 
preliminary hydrographic data at sea and made available for everyone on the 
cruise. Approximately 2600 CFC samples (including duplicates) were collected. 

Problems 

Initially there was a very high F11 blank: this blank decreased over time and 
was well documented so appropriate corrections could be made. One system was 
inoperable for the first week of the cruise. Occasional blank problems 
developed over the course of the cruise but were corrected and presented no 
problems for data quality 



7.  MOORING WORK 
    (Knut Aagaard, Jim Johnson, Rebecca Woodgate) 

Three physical oceanographic moorings were deployed and recovered on this 
cruise. 

___________________________________________________________________________

                                                   | Record Mean 
ID        Latitude      Water   Inst.   Inst. #    | Days    Velocity  Speed
          & Longitude   Depth          Depth  Days | Mag     Dir       (cm/s)
          (m)           (m)                        | (cm/s)  (deg)
---------------------------------------------------------------------------
CBL-A     76° 01.513'N   626    RCM-7   110   1    | 2.2     172       4.9
          168° 31.751'W (corr)  SBE-16  110   24   |
                                RCM-7   384   24   | 1.2     254       4.5
                                SBE16   385   24   |
                                                   |
CBL-B     76° 03.082'N  1090    RCM-7   116   22   | 0.9     257       4.2
          168° 50.984'W (corr)  SBE-16  117i  22   |
                                RCM-7   378   22   | 3.9     26        35.4
                                SBE16   379   22   |
                                RCM-7   848   22   | 1.4     73        5.2
                                                   |
CBL-C     76° 07.845'N  1617    RCM-7   100   23   | 1.7     161       5.9
          168° 59.155'W (corr)  SBE-16  101   23   |
                                RCM-7   370   23   | 0.6     86        2.7
                                SBE-16  371   23   |
                                RCM-7   820   23   | 2.6     73        4.0
                                RCM-7   1604  23   | 5.0     74        5.5
                                SBE-37  1605  23   |
___________________________________________________________________________


Deployments were made anchor first off the port stern of the ship, using a 
feeder-reel, the ship's capstan, a deck-mounted block which fair-led the line 
to a pulley mounted on the aft J-frame. A stopper chain was also suspended 
from the aft J-frame. 

Mooring deployment and recovery operations were performed with the ship DIW, 
to prevent mooring equipment being caught in the ship's screws. Thus, in this 
region of steep topography, setting the mooring at the correct depth required 
a knowledge of the ship's drift and the bottom bathymetry. Due to the added 
complication of ice, the moorings were designed such that lengths of mooring 
line could be removed or added to the original design during the deployment. 

Prior to mooring deployments, a CTD cast was taken at the required water 
depth. Then a bathymetry survey (consisting of a box of side 3 mile, centred 
on the CTD cast) was performed. A suitable start position for the mooring 
operation was chosen based on the ship's drift during the CTD cast and this 
bathymetry survey. Once the ship had repositioned, the current ship's drift 
was checked for ca.20 min before mooring operations commenced. If necessary, 
the ship was repositioned again. In practice, the ship's drift was almost 
unpredictable, being highly variable between different positions. Thus, 
significant adjustments were made during the mooring deployments to ensure 
the instruments were placed at the relevant water depths. 

Recoveries were also made off the port stern of the ship, using the same deck 
set up as for deployment. In general, ranging on the moorings was done from 
the landing craft, which maneuvered in amongst the drifting ice. By this 
method, the landing craft could wait in an open lead until the lead drifted 
over the mooring. This worked very well. For the first recovery, ranging was 
done from the ship. Due to comparatively rapid ice motion, this mooring 
surfaced under an ice floe. The mooring's position under the ice floe was 
estimated from ranging from the landing craft, and the Polar Star slowly 
approached the ice floe, almost stopped, and by gently pushing, split the 
floe such that part of the mooring bobbed into the open water. The landing 
craft tied onto this floatation package and, whilst this was being towed back 
to the Polar Star, the remaining parts of the mooring also came free of the 
ice. 

All the recovered SBE-16s gave good data. The SBE-37 shows excessive drift in 
its pressure sensor, but pressure information can be calculated from the 
other sensors on the mooring. One of the RCM-7s leaked seawater through the 
salinity cell and stopped recording after ca.1 day in the water. 

Preliminary results are give in the appendix. Semidiurnal oscillations 
(presumably tides) are a major feature in the current records. In the mean, 
however, there is significant velocity shear both between the moorings and in 
the vertical. The flow in the halocline is frequently perpendicular to the 
flow below. The velocities in the Atlantic layer show mean westsouthwestward 
flow for the duration of the deployment at the two shallowest moorings. At 
the deepest mooring, the flow below the halocline is instead to the 
eastnortheast and increases with depth. The T-S data show variability in the 
halocline and semidiurnal oscillations in the Atlantic layer. These records 
will be combined with the CTD and L-ADCP sections run at the mooring 
deployments and recoveries. 



8.  O18 AND BARIUM SAMPLING 
    (Marlene Jeffries, Kellie Balster, Wendy Ermold, Gail Grimes, Kelly
    Falkner,) 

For the halocline and surface waters, independent information on water mass 
origin can be obtained from 18O and Ba measurements (Guay and Falkner, 1997; 
Bauch et al., 1995; Cooper et al., 1997). In particular, oxygen isotopes have 
been used to distinguish between sea ice melt and river water distributions 
in the eastern (e.g., Bauch et al., 1995) and western Arctic (e.g., Macdonald 
et al., 1999), whilst the Ba signature may allow us to distinguish river 
water influence of North American versus Siberian origin (Guay and Falkner, 
1997). Other tracers (e.g. Si, N/P ratios, and the quasi-conservative 
parameters NO and PO) distinguish Bering summer and winter waters (Coachman 
and Barnes, 1961; Jones et al., 1998) from Atlantic contributions to the 
halocline (Jones and Anderson, 1986; Wilson and Wallace, 1990). In 
combination, this suite of measurements allows us to separate the surface and 
halocline waters into their component parts (Atlantic-origin halocline, 
summer and winter Pacific-origin halocline, ice melt, North American and 
Siberian runoff) and thereby delineate current pathways in the upper layers 
of the region. 

Almost 1000 O18 and Barium samples were taken on the cruise. The focus was on 
the upper 500m of the water column. A standard cast would take 10 samples, 
with a strategy aiming at samples from "surface", 20m, 35m, 50m, the Alaskan 
Coastal water subsurface temperature maximum at about 50-70m, 100m, the 
33.1psu salinity in ca 150-180m, the 34.2 psu salinity, the core Atlantic 
water temperature maximum, and below the temperature maximum. Full water 
column profile were also taken at the junctions of sections 8 and 9, 9 and 
10, 10 and 11, and 11 and 12. These samples will be analyzed on shore by 
Kelly Falkner at Oregon State University. 

References

Bauch, D., P. Schlosser, and R.G. Fairbanks, Freshwater balance and sources 
     of deep and bottom waters in the Arctic Ocean inferred from the 
     distribution of H218O, Progr. Oceanogr., 35, 53-80, 1995. 

Coachman, L.K., and C.A. Barnes, The contribution of Bering Sea water to the 
     Arctic Ocean, Arctic, 14, 147-161, 1961. 

Cooper, L.W., T.E. Whitledge, J.M. Grebmeier, and T. Weingartner, The 
     nutrient, salinity and stable oxygen isotope composition of Bering and 
     Chukchi Seas waters in and near the Bering Strait, J. Geophys. Res., 102, 
     12,563-12,573, 1997. 

Guay, C.K., and K.K .Falkner, Barium as a tracer of Arctic halocline and 
     river waters, Deep-Sea Res. Part II, 44, 1543-1569, 1997. 

Jones, E.P. and L.G. Anderson, On the origin of the chemical properties of 
     the Arctic Ocean halocline, J. Geophys. Res., 91, 10,759-10,767, 1986 

Jones, E.P., L.G. Anderson, and J.H. Swift, Distribution of Atlantic and 
     Pacific waters in the upper Arctic Ocean: Implications for circulation, 
     Geophys. Res. Lett., 25, 765-768, 1998. 

Macdonald, R.W., E.C. Carmack, F.A. McLaughlin, K.K. Falkner, and J.H. Swift, 
     Connections among ice, runoff and atmospheric forcing in the Beaufort 
     Gyre, Geophys. Res. Lett., 26, 2223-2226, 1999. 

Wilson, C., and D.W.R. Wallace, Using the nutrient ratio NO/PO as a tracer of 
     continental shelf water in the central Arctic Ocean, J. Geophys. Res., 95, 
     22,193-22,203, 1990. 



9.  RADIOACTIVE ISOTOPE SAMPLING 

Analysis of other isotopes (tritium, helium, iodine and cesium) also gives 
information about the history of a water mass. The waste outflow from nuclear 
reprocessing plants in Europe contains trace quantities of I-129 and Cs-137, 
so these tracers can be used to identify Atlantic influence. The atomic bomb 
tests of the 1960s were a source of radioactive enrichment of the surface 
waters. Combined with knowledge of background isotopic levels, water sampling 
of these isotopes can give information on the age of a water mass. 

On this cruise, samples were taken for Helium, Iodine and Cesium isotopes. 

Helium Sampling
(Wendy Ermold, Marlene Jeffries, Kellie Balster, Gail Grimes, Peter 
Schlosser) 

A total of 108 copper tube samples for Helium were taken on the cruise, 
concentrated on four of the sections, viz, section 2, section 6, the eastern 
end of section 11, and the penultimate CTD section, that run from the 
southern Northwind Abyssal Plain up onto the Chukchi shelf. On these 
sections, the CTD casts at ca.600m, 1000m and 1700m were sampled, with one 
sample taken in the "surface" layer, one in the Being inflow, one in the 
upper halocline water, one in the lower halocline water, three taken around 
the temperature maximum of the Atlantic layer (the Fram Strait branch), and 
five taken below the temperature maximum in the Barents Sea branch. These 
samples will be analyzed on shore by Peter Schlosser at the Lamont-Doherty 
Earth Observatory. 

Iodine-129 and Cesium-137 Sampling
(Kellie Balster, Marlene Jeffries, Wendy Ermold, Gail Grimes John Smith) 

A total of 96 one-liter samples were taken for I-129. A total of 27 samples 
(each 20 or 30 liters) were taken for Cs-137. These samples were taken (at 
reduced coverage) from the same casts and depth as sampled for Helium. At any 
cast, only three water depths, corresponding to the lower halocline waters, 
the core of the Fram Strait Branch and the core of the Barents Sea Branch, 
were taken. The shallowest cast on section 2 was also omitted. These samples 
will be analyzed on shore by John Smith at Bedford Institute, Canada. 



10.  DENITRIFICATION NITROGEN:ARGON SAMPLING 
     (Kellie Balster, Al Devol) 

The process of denitrification in the ocean removes nutrients from the water 
column, impacting the ocean's ability to take up carbon dioxide from the 
atmosphere through photosynthesis. In sediments and in the water column where 
dissolved oxygen values are low, microbes will also scavenge oxygen from 
nitrate and nitrite, releasing nitrogen gas into the water. Thus elevated 
levels of nitrogen gas are an indicator of denitrification having occurred. 

As part of her Master's thesis work at University of Washington, Kellie 
Balster took 21 "egg" samples for analysis of Nitrogen:Argon ratios and 
Nitrogen isotopes from 5 shelf stations on the cruise. These samples have 
been analyzed on shore at UW. Roughly half suggest evidence of 
denitrification. This topic will be pursued with reference also to the 
nutrient data. 



11.  LOWERED ACOUSTIC DOPPLER CURRENT PROFILER MEASUREMENTS
     (Wendy Ermold, Sarah Zimmermann, Marlene Jeffries, Kellie Balster,
     Rebecca Woodgate) 

Two RDI workhorse (300kHz) ADCPs kindly loaned to the project from Bob 
Pickart and Dan Torres (WHOI), were mounted on the CTD rosette. The upward-
looking instrument is slaved to the downward-looking instrument. (Although 
the ping sequence sounded synchronized, a ping synchronization error flag 
appeared during data processing.) The instruments are internally recording. 
Power during the cast comes from a rechargeable lead-acid battery pack also 
mounted on the CTD rosette. This battery was charged between casts using a 
standard battery charger. Due to out-gassing during charging, a vent plug 
must always be open during charging. (A few m of plastic tube were inserted 
in this plug hole to allow venting whilst preventing entry of water into the 
battery. This long hose acted as an extra reminder to replace the vent plug 
before deployment.) Care must be taken not to over charge this battery!! 

A few minutes prior to every cast, the ADCPs were started using Dos command 
routines written by Dan Torres. From cast #32 and subsequently, this start 
procedure included checking the ADCP clocks against GMT and resetting the 
ADCP clocks when they differed by more than a few seconds from GMT. The 
upward ADCP was started first, then the computer connection swapped to the 
downward ADCP (the master) by a toggle switch in the lab. Once both ADCPs 
were started, both communications cables were removed and dummy plugs 
installed. The battery dummy plug was also replaced. For a successful 
deployment, both ADCPs would be pinging both before deployment and after 
recovery. On recovery, the connectors were rinsed with fresh water, the 
communications cables reconnected, the battery vent plug removed and the tube 
inserted, the battery charger turned on, and the data downloaded. The battery 
charger was switched off once the charging current fell below 0.3A. 

Upward- and downward-looking profiles of velocity shear were collected at 
almost every CTD cast. For a handful of casts, only one ADCP was started due 
to operator error. For two further casts, problems in the communication 
cables between the lab and the instruments resulted in data being lost. On 
occasions the battery would not charge initially after recovery. Waiting for 
the battery to warm up and/or unplugging and replugging the battery cables 
fixed this problem. 

Initial on-board processing was done using the Sep2002 Version 7a release of 
the LDEO LADCP software. (Casts 1-19 used the older version of the software, 
but will be reprocessed on land.) 

To correct for ship drift during the cast, it is essential that the start and 
end positions of the ADCP going in the water are accurately recorded. An 
error of 20m in these positions results in a barotropic velocity error of ca 
1cm/s for a 1 hour long cast. (The expected currents are of order a few 
cm/s.) The positions recorded by hand by the operator were subject to error 
(both human error and system error when the data display would freeze for 
several seconds or even minutes) and thus were checked/corrected with 
reference to the GPS position recorded by the ship's data network. Initial 
processing did not account for the offset in physical location between the 
ship's GPS antenna and the launch site of the CTD rosette. 

The software allows use of the pressure time series from the CTD for 
comparison with the integrated vertical velocity from the ADCP. This requires 
a synchronization of the ADCP and the CTD clocks, all of which have distinct 
clock drifts. For this initial processing, no correction was made for the 
disparate clocks, although records exist to do this correction. The CTD clock 
was generally not more than 1 minute off the ADCP clocks, which themselves 
differed by a maximum of 7 seconds. 

Preliminary results are inconclusive. The target strength, though weakening 
midwater column in deep water, is reasonably strong. The final error in the 
measurement is generally between 2 and 10 cm/s depending on cast. The final 
velocities are of this order. It remains to be seen if these errors, combined 
with the error in extracting the tidal signal from the data, remain smaller 
than the measured velocities. 



12.  XBT WORK 
     (MSTs) 

A total of 53 Sippican Deep Blue XBTs were kindly made available to the 
project by the ship. These resulted in 47 successful casts at 41 locations. 
The six failures were caused by ice or by instrument problems. Six further 
casts were repeated where the earlier cast was bad, or terminated too shallow 
to reach the Atlantic temperature maximum. Both XBT systems on the Polar Star 
were used. That in the aft wet lab was more convenient, being a 1-person job 
and also having the GPS position automatically routed to the file. (The 
system in the met lab requires the position to be handtyped before the probe 
is launched. In regions of medium ice cover, this could occur 10 minutes or 
more before enough open water was available to launch the probe.) 

The XBTs were thrown on sections 2, 6, 7, 10, 11 and the 2 final CTD sections 
from the southern end of the Northwind Abysal plain up into the Chukchi shelf 
to the west, and back down from the Chukchi shelf towards the Chukchi abyssal 
plain, as fill-in between the CTD casts to better define frontal structures. 
A final section of 8 XBTs were thrown on the final steam to Barrow, to help 
define the pathways of the Chukchi waters over the shelf. 



13.  BATHYMETRY AND UNDERWAY MEASUREMENTS 

The USCG kindly installed a Knudsen echosounder on the Polar Star before the 
Arctic West 2002 mission. This data proved vital to the success of the 
Borderland cruise, since the best available bathymetric charts were far from 
accurate. This data, along with underway data, are stored with latitude, 
longitude and ship information, every 10 seconds or more frequently. Of the 
underway data, the wind data is considered reliable, whilst the barometric 
pressure and relative humidity are likely inaccurate. Temperature data is 
also recorded, but is substantially erroneous. 



14.  EDUCATIONAL OUTREACH 
     (Gail Grimes, Rebecca Woodgate) 

As part of the outreach activities of the project, Gail Grimes, a science 
teacher from Lake Stevens High School (just north of Seattle) took part both 
in the cruise and in school visits before and after the trip. 

As well as being part of the hydrography team, Grimes sent daily updates from 
the ship to a public website, to be read by her class and by other schools 
and individuals across the country and around the world. This site is 
available at http:\\psc.apl.washington.edu\CBLteacher.html. It features 
articles about the science projects on the cruise, life aboard ship, what it 
takes to be an oceanographer or a member of the Coast Guard, as well as 
lighter articles concerning "Cindy, the shrinking head" and just how many 
layers of parkas and waterproofs one needs to water sample. 

The website attracted over 3000 individual visitors over the 2-month period 
of the cruise. Fourteen schools or organizations registered, and 31 questions 
were sent to the website from the general public. 

Prior to sailing from Barrow, Grimes and Woodgate visited the three schools 
(Elementary, Middle and High) in Barrow to explain the oceanographic research 
in general and the purpose of this cruise in particular. They taught the 
classes about the ocean currents carrying Pacific waters from low latitudes 
up to Barrow and the Arctic, illustrating the journey by introducing the 
animals that might be encountered on the way by 2 water parcels (named Brian 
and Sid) starting in the Pacific. (On reaching the Chukchi Sea, Brian turns 
east and goes to Barrow, whilst Sid heads north into the high Arctic and 
meets the Ship.) The High school class also learnt about salinity and the 
circulation of the Atlantic waters in the Arctic. To illustrate the 
differences in water properties, the class learned how to use their own 
"human salinometer", i.e. their tongues, to distinguish between fresh water, 
Pacific waters, and Atlantic waters. To illustrate the effects of ocean 
pressure, Grimes also provided a styrofoam model head and the Barrow Arctic 
Science Consortium (BASC) kindly provided a collection of styrofoam cups for 
the Elementary and Middle school classes to decorate. The cups and the head 
were sent down with the CTD during the cruise and returned, shrunk by ocean 
pressure, to the classes in visits post-cruise. We are grateful to BASC for 
arranging these classroom visits for us. 

Grimes also enrolled for and passed course OCEAN 499B Undergraduate Research 
at the College of Ocean and Fisheries Science, University of Washington. 

APPENDICES 

Table of CTD and XBT casts 

Preliminary Hydrographic Sections

The following sections are contour plots of preliminary hydrographic data 
contoured using the Java Ocean Atlas program. The y-axis is CTD pressure in 
dbar. The x-axis is along-track distance. Major topographic features are 
indicated beneath the figures by the following abbreviations: 

    CS = Chukchi Shelf 
    MR = Mendeleev Ridge 
    CC = Chukchi Cap 
    NW = Northwind Ridge. 

For orientation, please refer to the track map at the beginning of the 
report. Tick marks on the top of the sections indicate the individual CTD 
casts. Data is interpolated between stations even where the station spacing 
is large (e.g. between the penultimate CS and final NW markers). Color scales 
may vary between plots. The color bar is standard rainbow (red, yellow, 
green, cyan, blue, purple). The values corresponding to red, green and blue 
are marked with each contour plot. Temperature sections are insitu 
temperature. 

The following plots are included: 
 
______________________________________________________

Temperature  0-300db   250-600db  500-4000db  0-4000db
Salinity     0-300db   250-600db  500-4000db  0-4000db
Sigma-0      0-300db   250-600db  500-4000db  0-4000db
CTD Oxygen   0-300db   250-600db  500-4000db  0-4000db
SiO3         0-500db   0-4000db
PO4          0-500db   0-4000db
NO3          0-500db   0-4000db
NO2          0-500db   0-4000db
F11          0-4000db
F12          0-4000db
F113         0-4000db 
______________________________________________________


Preliminary Mooring Results

  •  Current meters and seacats (temperature, conductivity sensors) were set 
     to record hourly. The following plots are included: 
  •  Stickplots for current meters on moorings CBL-A, CBL-B, CBL-C 
  •  Progressive vector diagrams for current meters on moorings CBL-A, CBL-B, 
     CBL-C 
  •  Time series and T-S plots for all seacat instruments. 
  •  The data for these plots has been calibrated using pre-deployment 
     calibrations. The progressive vector diagram and stickplots have been 
     corrected for magnetic declination (ca.16 deg.). The salinities are 
     calculated from conductivity using the insitu pressure at the SBE. The 
     pressure sensor on the microcat at ca.1600m on CBL-C is obviously 
     faulty. A constant pressure equivalent to 1628m depth has been assumed 
     for the salinity calculation. Final pressures will be determined with 
     reference to the post-calibrations, depth sounding and mooring length, 
     other instruments on the mooring and nearby CTD casts. In all plots, the 
     data is unfiltered.

Ice Charts 

The climatological ice cover in the region is 7-10/10ths. During the cruise, 
however, much lighter ice conditions were encountered, especially in the 
north western limits of the cruise track, where substantial leads and ice 
free areas made progress extremely fast. These regions are not reflected in 
the Ice Analysis charts of NOAA (the following pictures). 

Throughout the cruise, when weather permitted, the helicopters would fly on 
ice reconnaissance missions along the proposed cruise track. The ship 
received RADARSAT imagery from the National Ice Center approximately every 
day, and this information proved extremely helpful for planning purposes, the 
high resolution showing clearly the significant areas of open water between 
large floes. The heaviest ice was encountered on the initial approach to 
section 2, on the return up into the Chukchi Plateau (junction of sections 9-
10) and the southwestward run after the junctions sections 11-12. The CBL-A 
mooring was in ca 10/10th new ice when we returned to recover it. The final 
two sections of the cruise (westward up the Northwind Ridge and into the 
southen Northwind Abysal Plain, and up onto and back off the Chukchi shelf) 
were in open water save for the last few stations. 

_____________________________________________________________________________

Cruise Diary 
-----------------------------------------------------------------------------
OCTOBER 2001	
Wednesday 31st   Woodgate, Johnson, and Aagaard visit Polar Star in Seattle. 

MAY 2002	
Wednesday 1st    CBL planning meeting on Polar Star - UW, SIO, USCG. 
Thursday 2nd	

JUNE 2002	
Week 10th-14th   Loading of Polar Star in Seattle. 

JULY 2002	
Tuesday 9th      Polar Star sails from Seattle for SBI mooring cruise. 

AUGUST 2002	
Thursday 15th    M.Johnson, Mathieu, Zimmermann join ship in Dutch Harbor 
                 for instrument set up during transit to Barrow. Woodgate 
                 and Grimes arrive in Barrow for educational outreach. 
Friday 16th      Woodgate and Grimes visit 3 schools in Barrow. Polar bear 
                 sighted on ice off Barrow. 
Saturday 17th    SIO science party arrives in Barrow. Polar bear (mother 
                 plus cub) in Barrow rubbish dump. 
Sunday 18th      Remainder of science party arrives in Barrow. 
Monday 19th      Science party transferred from Barrow to Polar Star by 
                 ship's helicopters. Science equipment set up. First ice 
                 around 9pm local time (GMT-8).
Tuesday 20th     Science set-up continues. Test CTD cast (998) run 
                 successfully. 
Wednesday 21st   Science set-up continues. Around 11am local turn ship for 
                 Barrow for Medivac accomplished by land based helicopter ca 
                 7pm local. 
Thursday 22nd    CTDs 1-2 Arrive at first cast ca 2pm local time. Proceed 
                 down line 2, the mooring line, running CTDs and XBTs 
                 through the night. Some 10/10th ice cover. 
Friday 23rd      CTDs 3-5 Run bathymetry surveys and deploy moorings CBL-A 
                 and CBL B. Run CTDs and XBTs along line 2. 
Saturday 24th    CTDs 6-8 Run bathymetry survey and deploy mooring CBL-C. 
                 Complete line 2 of CTDs and XBTs. Skip sections 3 and 4 and 
                 head for section 5. 
Sunday 25th      CTDs 9-11 Run CTDs along line 5. Skip the repeat of the 
                 slope stations and the shallowest cast in anticipation of 
                 heavy ice conditions in the north. Problems with the winch 
                 controller (pauses in paying out or heaving line). Work 
                 around these issues by using manual joystick control 
                 instead. 
Monday 26th      CTDs 12-13 Steam most of the day to reach the start point 
                 of line 6. Change gears on manual control of winch to allow 
                 lowering at 60 m/min. Recommence CTD on line 6 around 
                 midnight. 
Tuesday 27th     CTDs 14-17 Continue CTD and XBTs up line 6. Still 
                 sufficient open water and leads for CTD casts. 
Wednesday 28th   CTDs 18-19 Continue CTD and XBTs up line 7. 
Thursday 29th    CTDs 20-22 Continue CTD and XBTs up line 7, into deeper 
                 water. Cut from line 7 north to line 8 and head back east, 
                 CTDing. Evening lecture "A Street Guide to the Arctic". 
Friday 30th      CTDs 23-29 Continue CTDing along line 8. Large areas of 
                 open water. (several CTDs done with hardly any ice in 
                 sight. Start to worry about sea state!) Move south from 
                 original trackline to capitalize on large leads. Zigzags in 
                 ship's track show attempts to move back north. Note bottom 
                 topography complex here, may influence interpretation of 
                 CTD data. Very steep drop-offs in places. 
Saturday 31st    CTDs 30-33 Continue CTDing along line 8. Again large areas 
                 of open water and leads tending south of original 
                 trackline. Pizza Night (made by science party). 

SEPTEMBER 2002	
Sunday 1st       CTDs 34-36 Turn the corner at line 8 after a deep cast and 
                 head back up onto the Chukchi Plateau, line 9. To 
                 accommodate high station density, subsample the nutrient 
                 profiles. Note evidence of ship's outflows in top few 
                 meters of CTD casts. End of the balmy weather we have been 
                 having. Water now starting to freeze, and progress much 
                 slower. 
Monday 2nd       CTDs 37-40 Labour day (i.e. Sunday routine). Water still 
                 freezing, ice much heavier. Speed made good nearer 4 knots, 
                 and hard to find suitable lead in the ice for the CTD. Skip 
                 2000m station as ice too heavy. Bottom also steep up into 
                 plateau, 0.5nm drift during CTD cast changes depth by 100m. 
Tuesday 3rd      CTDs 41-47 Beautiful sunny day. Ice heavier again. Finish 
                 line 9 and head back out on line 10 with CTDs and XBTs. 
Wednesday 4th    CTDs 48-52 CTDing out line 10. Grimes (our teacher) ill. 
                 Topography very steep off Chukchi Cap, and hard to find a 
                 hole in the ice at the right depths, so station depths 
                 variable. 
Thursday 5th     CTDs 53-57 CTDing out line 10 into deeper water. Another 
                 gloriously sunny day. Ice melting again. 
Friday 6th       CTDs 58-62 CTDs and XBTs back south along line 11. Station 
                 spacing very close as topography steep again. Sun and 
                 sudden fog (canceling flight ops). Two seals sighted. 
Saturday 7th     CTDs 63-65 Continue CTDs and XBTs along line 11, again at 
                 close station spacing. Pinewood Derby held in heli hanger 
                 in the evening. 
Sunday 8th       CTDs 66-71 More CTDs up the slope. Track again south of 
                 original plan following leads in the ice. Appear to follow 
                 a gully through the ridge (7nm all the same depth), so turn 
                 back N to regain original track. 
Monday 9th       CTDs 72-76 More CTDs, now down off the ridge into the deep 
                 basin. Styrofoam head passes CFC airsample test and so is 
                 put down on the deepest cast. Unusual upper water column 
                 structure at the deepest cast (76). Head back up slope 
                 (start of line 12), but do not repeat deep stations on the 
                 Northwind Ridge. 
Tuesday 10th     CTDs 77-79 Leak in cooler for port shaft. DIW from ca.2am-
                 noon. Fog and heavy ice makes progress very slow. First 
                 Polar Bears in weeks (mother plus 2 cubs) approached ship 
                 during CTD cast in early morning. 
Wednesday 11th   CTDs 80-85 Patriot Day. More CTDs, along line 12 into 
                 Northwind Abyssal Plain. Sign of bottom boundary layer in 
                 stations on the Plain, possibly related to waters entering 
                 the region through gaps in topography from the north. 
Thursday 12th    CTDs 86-91 As have made good progress, divert from line 12 
                 WNW at the north end of the Northwind Abyssal Plain and 
                 head back up onto the Chukchi Cap. Topography again VERY 
                 steep. 
Friday 13th      CTDs 92-96 Polar Bears sighted in the early morning. 
                 Trouble shooting blown fuse in engine controller means DIW 
                 for ca 3 hours (some of that CTD cast). Proceed on 2-2-1 
                 engine configuration as ice sufficiently light. Large areas 
                 of open water, and ice avoidance takes us 6nm off original 
                 trackline. CTDs and XBTs across plateau and back down the 
                 western side. 
Saturday 14th    CTDs 97-100 Finish CTD line. Start engine work during last 
                 deep cast (pre breakfast). Underway again around 1pm, 
                 headed for moorings. Ice VERY light (max speed 17 knots), 
                 so rerun deep CTD stations on the mooring line. 
Sunday 15th      CTDs 101-102 Rerun deep CTD stations on the mooring line. 
                 Drive past CBLC as ice quite heavy. Start mooring recovery 
                 at CBL-B at first light. Mooring up under ice, but 
                 recovered by skillful ship maneuvering and towing the 
                 mooring from the small boat. Proceed to CBL-A but ice 
                 coverage ca.10/10th (if thin). Return to CBL-C, and 
                 recover, after ranging from small boat. Polar bear 
                 footprints at CBL-B and CBL-A mooring sites. 
Monday 16th      CTDs 103-106 CTD through the night. At CBL-A at first 
                 light. Recover after many hours of waiting for ice drift. 
                 (More Polar Bear footprints and a walrus.) Two CTDs to 
                 complete rerun of mooring line. Head to Barrow. 
Tuesday 17th     Aagaard and Johnson flown off to Barrow by ship's 
                 helicopter. Head north in open water to do CTD line up 
                 Northwind Ridge. 
Wednesday 18th   CTDs 107-111Recommence CTDs west up Northwind Ridge. 
                 Problems with L-ADCP. Open water, significant ship drift 
                 during stations. 
Thursday 19th    CTDS 112-119 Continue CTD line into southern end of 
                 Northwind Abyssal Plain. Station 114 is intercalibration 
                 cast with Canadian cruise. Turn WSW after station 116 to 
                 run CTD and XBT section back up onto the slope. 
Friday 20th      CTDs 120-126 From shallowest station, run CTD and XBT line 
                 down slope towards WNW. Since Barrow, all but the last few 
                 casts have been in open water. End of science at 2100 
                 local. (Last CTD on deck at 2055.) 
Saturday 21st    Head back for Barrow, science party packing up. Run final 
                 XBT section across slope on this last leg. Evening skits. 
Sunday 22nd      Packing up. 
Monday 23rd      Science party transfered to Barrow by helicopter, Polar 
                 Star standing some miles off to the south west. Some of 
                 science party depart on evening flight. (During our 
                 absence, many polar bears have been sighted in Barrow.) 
Tuesday 24th     Grimes and Woodgate revisit Middle and Elementary schools. 
                 Remainder of science party deparst Barrow on both morning 
                 and evening flights. 

OCTOBER 2002	
Monday 7th       Polar Star arrives back in Seattle. Week 21st-25th Polar 
                 Star offload in Seattle. 
_____________________________________________________________________________


In transit Reports from the Polar StarReport from Chief Scientist, Rebecca 
Woodgate, August 27, 2002 

Greetings from the Chukchi Sea, sitting in ice and sun. We've been out 48 
hours and already it seems like a lot longer (though not in the bad sense!) 
We've been busily at it, setting up instruments and did the test casts on the 
CTD last night. There was a little preening still to do, but now we are "good 
to go" and just need to finish the transit through the ice to the first 
station. 

The Polar Star arrived Monday as planned, but stood 15 miles off the coast 
due to ice. The helicopter transfer over to the ship on Monday, August 19 was 
as fun as ever, and we've not really stopped since. It's good to be out, 
after kicking our heels in Barrow for the last few days. Gail and I did the 
rounds of the school classes. GREAT schools, very modern and bright, and keen 
teachers and kids. Small classes, and a great interest in science. 
Oceanography for 7 year olds -will we be forgiven for likening the complex 
CTD-Rosette to a complicated bucket? Or the mix of waters in the Arctic (the 
Atlantic and Pacific) as being the equivalent of American (i.e. all now 
Arctic, but with their origins somewhere else). Or the fact that we can trace 
the waters from either ocean just like how they could tell that I "wasn't 
from around here"? Fun stuff, waving around globes and maps, though unlike at 
a conference, the school bell is the ultimate deadline. 

The coast in Barrow was solid with old broken-up floes that had just blown in 
a few days before. The locals were out fishing, standing on the ice just a 
few feet from the shore, with lines on short rods. They'd stand for hours, 
but I never saw a catch. We DID see polar bears though, one out a few hundred 
yards on the ice, and obviously with a mission of his own. Also, a mother and 
cub, this time on land, and prompting the police to close the road so the 
bear and her cub could be encouraged back out on the ice. A science talk took 
us out for a walk on the tundra, which isn't as barren as one might expect. 
Browns now, but evidence of flowers from the summer, reminded me of Scotland, 
though a LOT flatter, and you get less caribou in Scotland. Rebecca 

Report from Chief Scientist, Rebecca Woodgate, August 22, 2002 

Gail's been having email problems, but that should be solved soon. Gotthe 
second CTD cast in today, and progressing to the 3rd. We're tight on people 
till the moorings are all in. Should start that tomorrow am. Fingers crossed. 
The ice is a variable feast, but so far so good. Jim was right about the ship 
shaking though! Lots of sweet corn, peas, pasta, meatloaf, pork tonight, 
anything you can think of for breakfast and a line of cakes that gets better 
every day. All is well. Rebecca 

Report from Chief Scientist, Rebecca Woodgate, August 27, 2002 

Greetings from the Arctic ice -supposedly 9-10/10ths ice cover. Despite that 
forecast, we have frequently been lucky enough to find large leads of open 
water through the ice, and can make a heady 7 knots (equivalent to a 
reasonable jogging pace) or more. Here's hoping that continues. When we 
really hit the 9-10/10ths, we'll be making more like 2 knots (a country 
stroll pace) or less. Barrow is now just over a week and 500 miles behind us, 
the latter as the crow flies (well, ok, Arctic tern perhaps, though we've not 
seen many), not according to our track which is nearer 1000 miles, and our 
experiences. We are in the southwestern most region of our CTD box, with the 
three moorings behind us in the water, recording stoically (I assume) until 
our return. 

From Barrow we headed straight to the mooring and CTD line -an ambitious 
start with both mooring and CTD teams working long hours to get both 
operations up and running quickly. The ice was kind to us on the mooring 
deployments, though finding open water to deploy was still a reasonable 
challenge. We deploy the moorings with the ship nuzzled against the ice, and 
drifting with the wind, so, since we are aiming for certain water depths in a 
region of moderately steep (and poorly known) topography, determining the 
drift is important, but tricky. Anticipating the latter, we had designed the 
moorings to be adjustable for water depth, and when a steady 0.3 knot across-
isobath drift turned into dead calm, we were glad we had the flexibility! So, 
now all three moorings are out, sampling the temperature, salinity and 
velocity structure of the Arctic Ocean boundary current hourly. Already 
thoughts turn to the recovery at the end of the cruise. Much of the ice near 
the mooring site was "rotten" (1st year ice, melting away under solar 
insolation), so we can hope for at least equally open water on our return in 
a month. 

Since the moorings, we have swung into a CTD routine. Two 12-hour watches 
cover us through day and night, though with the midnight sun (or midnight 
fog) the distinction is really one of meal timings. We are now approaching 
our 17th cast. Winch issues temporarily slowed the CTD casts, but we now have 
a work-around and are back up to the maximum drop speed (60 m/min) the CTD 
likes, and we are set to CTD and sample from now till we get back to the 
moorings. I'll write more next time on the water sample programs. I wouldn't 
like to get ahead of the reports from our teacher! I hope you've looked at 
the website, especially the "getting dressed for being sampling cop" section. 
And there was me thinking Gail was just liking the food (which is, as I know 
you'll be wondering, very good, especially the cakes!). All's well out here. 
With the willing help of the ship's crew, who are marvelous, we are well on 
our way! Look after the mainland for us. Best regards, Rebecca 

Report from Chief Scientist Rebecca Woodgate, August 31, 2002 

A quick update for the weekend. CTDing away here merrily. The ice suddenly 
opened up. They did casts last night where there was no ice to be seen and 
ship's roll started to be noticeable! We topped 14 knots at times today, but 
now are back to the more usual 5 or 6. She's a BIG powerful ship. While other 
icebreakers will fall into a crack they make in the ice, changing their 
heading to go with the crack, the Polar Star just carries straight on. Must 
run. CTD just on deck. 

Take care all, Rebecca 

Report from Chief Scientist Rebecca Woodgate , September 1, 2002 

Greetings from the Arctic! All well and things are going smoothly. There's 
been a substantial amount of open water and wide leads, and we've been making 
good time. Our cruise track would look a little odd without knowing about the 
leads, which take us significant distances from our direct route. Still, it 
makes more sense to move faster in a circuitous manner than force our way 
along a dead heading. The CTD casts progress at a fine pace. The chemical 
analyses run around the clock, and we are taking advantage of our promising 
progress to catch a few more CTD profiles in key spots. 

The data are "lovely"-very clean, no ship roll and almost zero interference, 
a surprising amount of fine structure temperature/salinity steps, and other 
intriguing things. I'm not going to hypothesis on unfinished sections, but 
it's turning out very nicely so far. I sit now in the "science library", a 
computer lab one deck below the working (our CTD) deck. A TV screen in the 
corner acts as a repeater for the outside cameras (pointed forward, aft, down 
on the CTD) and the bridge navigation screen. A feed from the ship's science 
data system gives me real time depth and course information, so I can work at 
the computer whilst still monitoring exactly how we are getting on! 

You really have to remind yourself to go outside (other than to launch the 
CTD). Weather is definitely getting colder. During the cast, a thin layer of 
ice starts to form on the water and recently we've had dustings of snow. That 
helps to remind you where you are, especially when we've done casts in leads 
so big you can hardly see any ice! SO -all well here. Hope things are well 
back on dry land! Rebecca 

Report from Chief Scientist Rebecca Woodgate, September 10, 2002 

Greetings from a foggy/sunny Northwind Ridge! Tuesday and the 77th cast. We 
have been making very good progress, and are bringing in water samples just 
as fast as we can analyze them. The light ice has upped the work pace 
considerably, and the science team and the crew are answering the challenge 
marvelously. We've completed our deepest cast, some 3800m down to the foot of 
the Northwind Ridge and the Canadian Basin, and are now CTDing our way south 
back to the mooring site, with a little time in hand for some extra casts if 
things continue well. 

This early morning brought our first serious mechanical problem -a leak in 
part of a cooler for the port shaft, but a long night/morning from the 
engineers has us back in operation having lost only half a day. (We have 3 
shafts, each of which turns one propeller, so don't worry, we'll get home 
ok.) 

The data continue beautiful! We have cut forward and back across the boundary 
current core in the coastal and ridge sections, over the Mendeleev and up and 
down the Chukchi Plateau. The variety of structure is unexpected and the 
nutrient and CFC data will prove an important part of solving the puzzle. The 
Pacific waters are also showing intriguing variations, which in idle moments 
(had we any) one could link to the wildlife. In the wee hours of the morning 
a polar bear with 2 cubs approached the ship -the first sighting in weeks. 

With the Scripps team's onboard chemistry analysis and data quality control, 
it's like being a kid in a candy shop, as every new day brings newly 
processed and calibrated CTD and bottle data. The CFC team has two analysis 
instruments up and running, and is always hungry for water. They also tested 
the Styrofoam head brought aboard by our teacher to illustrate the effects of 
deep-sea pressure. Since it was given a clean bill of health, the head went 
down on the deepest station, along with Styrofoam cups colored by the school 
kids in Barrow and people aboard. I'll leave you to speculate on the results 
till the photos make the website! 

Our "teach" is back on form after a couple of days of sickness, which gave 
others the chance to be "reporter". It seems there is nothing to which our 
students won't turn their hand to. They are proving an indispensable and 
enthusiastic part of the team. Hump day has come and gone and with it, the 
Pine Wood Derby (a model car race, in which each competitor is given a block 
of wood and some wheels and has to build the fastest car they can). The 
science party made a very respectable showing, with three entries. Though we 
didn't win for speed, the CFC team won for style, with their model of the 
Polar Star, complete with helicopter. 

So all well in the high Arctic. I hope this finds you all as well as it 
leaves us, Best regards, Rebecca 

Report from Chief Scientist Rebecca Woodgate, Sunday 22nd September, En route 
to Barrow 

A quick closing email to wrap up the cruise. We are in the final throes of 
packing and tomorrow morning the Polar Star's helicopters should sweep the 
science party back to dry land. We've had an extremely busy and a productive 
35 days. The moorings are safely recovered, and the data looks good. Our 
hopes for light ice were unfounded, but a combination of waiting and 
extremely skillful ship driving proved successful. 

We brought our 126th CTD cast onto deck late Friday night, 25% more than we 
had originally hoped for. The lightness of the ice allowed us to 
substantially increase our spatial coverage of the Chukchi Borderland region, 
with extra sections over the Northwind Ridge and the Chukchi Plateau. A first 
look at the data shows a rich variety of features, pathways of Pacific 
waters, variability in Atlantic water structure, and much more. It's a gem of 
a dataset! 

It's hard to resist statistics on something like this. We brought up around 
30 tons of water for samples. We've analyzed over 2500 CFC samples, 2662 
nutrient tubes, 2999 oxygen flasks, 3066 salts, taken almost 1000 samples 
each for Barium and Oxygen-18 isotopes, around 100 for Iodine and Helium, and 
ca 30 for Cs. In total, the Rosette traversed almost 250 miles vertically, 
the equivalent of driving from Seattle to Vancouver and back. I could 
continue, but I won't! Instead, back to the packing and then to dry land! 
With best wishes from the Arctic, Rebecca 


UNOLS Report

MEETING OF PLANNED OBJECTIVES 100% or more 
Objectives -5 week physical oceanographic research cruise, including 
  
  •  CTD casts (target 100) 
  •  3 mooring deployments 
  •  3 mooring recoveries in a region with a climatological ice cover of 7-
     10/10ths. Completion -126 CTD casts 
  •  all moorings successfully deployed and recovered. The cruise 
     expectations were significantly exceeded, due to the dedication, 
     enthusiasm and tireless efforts of the Polar Star crew and the science 
     team and the exceptionally light ice cover in the region. The team work 
     and combined skills of the ship and science crews allowed us to overcome 
     the few technical hitches experienced at sea, such that their impact on 
     the science was minimal/zero. These hitches were: 
  •  issues with the winch controller 
  •  issues with interference on the CTD cable These, and other suggestions, 
     are discussed below. This list should not detract from the extremely 
     positive and successful experience we have had working with the Coast 
     Guard and the Polar Star. 


SCIENCE PARTY N/A 


SHIP OPERATOR PRE-CRUISE ACTIVITIES/SHORE SUPPORT Excellent 
The support we received from both the Science Liaison team and the crew of 
the Polar Star were excellent. Few points: 

  (1)  The planning meetings were exceedingly useful and productive. 

  (2)  We are particularly grateful for the speedy acquisition of the Knudsen 
       echosounder so close to the sailing date of the Polar Star. 

  (3)  Some email queries to/from the ship got lost stressing the importance 
       of a dependable email system (see below). 

  (4)  It would be helpful for planning purposes (including at the proposal 
       writing stage) for yet more information on the ship to be generally 
       available, for example on the website. Even experienced sea-going PIs 
       could be unfamiliar with the ship and the practices necessary to the 
       Polar Class (e.g. hub purification). The "Welcome Aboard" document is 
       an excellent example of pre-cruise information. The access to 
       dimensioned drawings of labs is also very useful, and could be extended 
       to include photos of the laboratory spaces. 


SHIP OPERATOR EQUIPMENT AND MSTS Excellent 

With the exception of: 

  •  the winch controller system, with which we experienced significant 
     difficulties during the cruise, particularly intermittent winch payout. 
     The problem was suspected to be a full computer hard disc, but rather 
     than experiment we opted to use the manual controls on the winch. This 
     worked well when combined with some extra wiring to allow readout of 
     'wire out' and rezeroing of 'wire out'. We understand the winch control 
     system is to be replaced during the current yard work. 
  •  significant electrical noise induced on the CTD signal wires that 
     transit from the winch slip rings down to the CTD deck unit (Forward Wet 
     Lab). The CTD telemetry line could be rerouted and separated from 
     potentially noisy EMF areas. (This fix was installed temporarily during 
     the CBL cruise.) 
  •  lack of reliability of the email system (both Inmarsat and Iridium). 
     Both worked at times. However, even within range of the Inmarsat 
     footprint, there were several incidences of incoming and outgoing emails 
     not being delivered. The Iridium worked spasmodically. Also, the 
     combination of different operating systems in the science library led 
     repeatedly to serious faults in email accounts. 
  •  during the CBL cruise, science email/internet access was set at 2 hours 
     a day out of the Coast Guard's 24hr access, since shipside or the 
     scienceside could not be connected simultaneously. Whilst this worked 
     reasonably enough for the CBL mission, the issue of increased science 
     internet access could be very important for other cruises. 
  •  poor readability of the bridge waypoint video display on monitors 
     elsewhere on the ship. To overcome this, the science party set up a 
     Nobeltec navigation program on a separate computer in the wetlab, linked 
     to a separate GPS system mounted near the CTD cast deck. This 
     independent system was an excellent tool for cruise planning and it 
     might be worth the Polar Star considering such a system as a tool for 
     science. 


Things that were particularly useful 

  •  the Knudsen echosounder 
  •  the science data system -this worked well and could usefully be extended 
     (e.g. to include winch parameters), and made more real-time (an issue 
     for some of the navigation parameters), more reliable (e.g. the data 
     stream when accessed from remote locations would frequently crash) and 
     more user-friendly (e.g. so that changing one variable does not require 
     taking the whole system down). 
  •  the TV screens repeating the camera views (could this be extended to 
     include winch parameters e.g. wire out?) 
  •  fume hood in wetlab (which appears to vent back into the wetlab) Other 
     suggestions for improving the science set up 
  •  junction boxes could be installed at the winch and in the lab for user 
     access to the CTD telemetry line (e.g. readouts of wire out, ways of 
zeroing winch, etc.) 
  •  Forward Wet Lab 
     -  some manner of accessing DI water directly in the wetlab (DI water is     
        currently only available in the engine room) 
     -  more electrical outlets (120VAC) 
     -  more network hubs 
     -  better access to science data (GPS, MET and Winch readings) 
     -  better access through exterior bulkheads for temporary cruise wiring. 
        (i.e.. for cables run from the lab to the rosette room or out to a 
        weather deck) 
     -  dedicated winch operator/lab communications, instead of VHF radios. 
     -  dedicated science storage space in lab (e.g. 
        drawers/shelves/cupboards) Currently available space is mostly full 
        with ship's equipment. 
  •  Science Library -this is a nice science space, which would benefit from 
     more (intercompatible) computers (see comments above on email) 

SCHEDULING Above average 

The final scheduling arrangements worked very well. Whilst none of us, I 
suspect, wish a repeat of the months of uncertainty in the spring when it was 
unclear what ship would be available for the mission, we realize that this 
situation arose from complex circumstances, and was (hopefully) unique. 

SAFETY ON BOARD Excellent 

We were fortunate in having calm seas for the launching and recovering of the 
CTD rosette. Given the confined cast deck, it is easy to see how the current 
operation gets shut down in bad weather despite the routine use of tag lines 
and poles. Some suggestions for the CTD operations: 

  •  use of a rigid docking mechanism or arm to stop the rosette from 
     swinging during recovery/deployment in rolling seas. (There are 
     reputedly some CTD launching systems used on NAVO ships which might be 
     suitable.) 
  •  a more substantial line/barrier to stop people from going into the 
     ocean during launch and recovery. (This would probably require lifting 
     the rosette higher during these operations, which might require 
     substantial modifications to the system.) 
  •  positioning of a life ring nearer to the rosette launch pad 

OFFICERS and CREW Excellent or higher. 

The enthusiasm and "can-do" attitude of the crew, especially the MSTs, 
Captain and Ops made the cruise the great success it was. Any concerns from 
the science team were solved promptly and courteously. In every circumstance, 
the ship went the extra mile to help us out. 

VESSEL AND EQUIPMENT/CONDITION/LIVING SPACES Above Average/Excellent 

Given the original design of the ship was not for research, the facilities 
aboard the Polar Star are exceedingly good. Naturally, more science space 
would be desirable, (lab space, deck space), but obviously that is not easily 
realizable. For the CBL cruise, a separate laboratory container was mounted 
on the port deck, and connected for power, phone, etc. This worked 
exceedingly well. To focus on improvements that would be achievable without 
structural work: 

  •  winch controller system (see above) 
  •  suggestions for wetlab (see above) 

Living Spaces 

  •  The "Welcome Aboard" document is wonderfully helpful. Could it also 
     include some maps to help with orientation? 
  •  the preliminary introduction to the ship is very good, and conveys a 
     lot of information. The cribsheet handed out is a good memory jogger 
     and could usefully be extended. Signs in staterooms (e.g. reminding of 
     what is/is not allowed down the toilets; location of cleaning supplies; 
     expectations of cleaning) might be valuable. 
  •  mixing scientists and crew in staterooms did not always work out 
     smoothly. 
  •  more substantial mattresses would be appreciated, as would more hooks 
     and towel racks in staterooms. 

These points are raised only for future reference. I would emphasis that the 
Polar Star responded fully and promptly to our concerns here, as in all other 
instances. 

  General Points 

     • the health requirements for the cruise were far less stringent than 
       those frequently required for participation in polar field work. For 
       operations this remote, these requirement should be revised, perhaps 
       to include a medical examination within the last ca.12 months. Number 
       of days lost to: 

Weather -none 

Ship's mechanical systems -1-2 

Ship's scientific equipment -none 

User scientific equipment -none 

Medical issues -2 



ACKNOWLEDGEMENTS 

The funding for this cruise was provided by NSF-Arctic Natural Sciences 
(OPP-0117480). We are indebted to the Captain and crew of the Polar Star, for 
their enthusiastic, energetic and professional support of this cruise, which 
made it both extremely successful and enjoyable. Our thanks go also the USCG 
Science Liaison LCDR April Brown and Dave Forcucci for answering all our 
needs pre-cruise and to the Barrow Arctic Science Consortium (BASC) for their 
support of pre- and post-cruise logistics in Barrow. 



CCHDO DATA PROCESSING NOTES
_____________________________________________________________________________

Date       Contact         Data Type  Summary/Notes
-----------------------------------------------------------------------------
2010-06-24  Muus           CTD/BTL    data files online 
            Notes for CBL02 Bottle and CTD data. Expocode 32PZ20020819. June 
            23, 2010.
            Original data files were prepared in 2004 for Jim Swift.
            (1)  Expocode changed from 32PZAWS02.2 to 32PZ20020819. Expocode 
                 on CCHDO website placeholder has been 32PZ20020815 based on 
                 an early cruise report.
                 Final cruise report and ODF data files show departure date 
                 as Aug 19, 2002.
            (2)  Parameter name for 18O:16O ratio changed from O18/O16 to 
                 DELO18.
            (3)  Flagged all nitrite values "3" that are deeper than 100db 
                 and greater than 0.02 (Stations 31, 34, 41-45, 60, 71, 104-
                 109, 111-112, 114-117).
                     Note from shipboard chemist: 
                 "I cannot find any analytical reason to correct the data for 
                 the mentioned stations. There are definite peaks in the deep 
                 samples. I am still not sure the data is real though. We 
                 were/are having the same problem with some of the calcofi data. 
                 We suspect it is due to dirty Niskins Bottles."
            (4)  Checked new bottle and ctd exchange files with JOA. 
_____________________________________________________________________________
