C.1.1. Highlights

WOCE I7N, R/V Knorr Cruise 145/10 in the Indian Ocean 

Expedition Designation (EXPOCODE): 316N145/10 

Co-Chief Scientists:

Donald B. Olson
RSMAS/MPO University of Miami
4600 Rickenbacker Cswy.
Miami, FL 33149 U.S.A.
Ph. (305) 361-4074
FAX: (305) 361-4662
TWX/TELEX 810/848-6067
email: dolson@rsmas.miami.edu

Scott Doney
National Center for Atmospheric Research
P.O. Box 3000
Boulder, CO 80307
Ph. (303)497-1639
FAX: (303) 497-1700
email: doney@ncar.ucar.edu

David L. Musgrave
Institute of Marine Science
University of Alaska
Fairbanks, AK 99775
Ph. (907) 474-7837

Ship:  R/V Knorr

Ports of call:  Pt. Louis, Mauritius to Muscat, Oman 

Cruise Dates:  15 July to 24 August 1995

C.1.2. Cruise Summary

Cruise Track:

The cruise track is shown in Fig. 1* with expanded depictions to show stations 
in the Amirante Passage and Oman coastal region in more detail in Fig. 2a*, b*.

Number of Stations:

There were 156 stations with CTD/rosette and lowered ADCP.  The rosette was a 
36 bottle rig with 10 liter bottles.  Details are included below. 

Sampling:
Measurements on the bottle samples included salinity, oxygen, nitrate, nitrite, 
phosphate, silicate, total CO2, alkalinity, C-14, tritium, helium, iodine, 
barium, CFC's 11 and 12.  Bottles were fired to catch extreme in properties and 
obtain a sampling frequency that included samples at least every 100 m in the 
upper layers and 300 m in the deep waters.  The bottle spacing is shown in Fig. 
3*.  Underway measurements included acoustic Doppler current profiling (ADCP), 
IMET meteorological sampling and continuous CO2 and NO2 measurements.

Floats, Drifters and Moorings:
Eleven ALACE floats were deployed as discussed below.  No drifters or moorings 
were deployed.

C.1.3. List of Principal Investigators

Table C.1:  The principle investigators involved in the cruise effort; cruise 
personnel and their duties are given in table C2. 

Analysis				Institution		Principal Investigator

Basic	Hydrography 			SIO			James H. Swift
(Salinity, O2, Nutrients, CTD)
CFC					RSMAS			Rana Fine
He/Tr					RSMAS			Zafer Top
AMS 14C and Ra-228			Princeton		Robert Key
TCO2 & Alkalinity			U Hawaii		C. Winn
TCO2					SIO			Charles Keeling
Barium					OSU			Kelly Faulkner
Transmisometer				TAMU			Wilf Gardner
ADCP and LADCP				U Hawaii		Erik Firing
ALACE Floats				SIO			Russ Davis
UW PCO2					Princeton		Robert Key
UW Air chemistry			U Hawaii		C. Winn
UW Meteorology (IMET)			WHOI			B. Walden
UW Thermosalinograph			WHOI


C.1.4. Scientific Program and Methods

The major contributions of I7 to the overall Indian Ocean WHP effort include:

1) Interior water mass properties and transports across the Mascarene Basin.  
   These will complement I3 which provides an east-west section through the basin 
   and is closed to the African continent by I7a (Toole).  The section is laid out 
   approximately perpendicular to the topography of the southern Mascarene plateau 
   out to the central Mascarene Plain at 55 E.  This portion of the cruise will be 
   modified to connect with Toole's line such that the combination forms a 
   continuous section in mid-basin.  The line moves northwards up the central 
   Mascarene Basin to a point northwards of the inflow from the break in the 
   Mascarene plateau at 17 S before cutting westward to close on the deep 
   topography north of the tip of Madagascar. 

2) Short section across the deep Amirante Passage to provide another 
   realization of the deep water mass properties and the baroclinic structure in 
   this important passage between the Mascarene and Somali basins.  This 
   complements the earlier work of Fieux and Swallow (1988), Barton and Hill 
   (1989), an April 1995 section by NOAA and a planned repeat cross section by I2.  
   The planed cruise track crosses the deep western boundary current upstream of 
   the Western Channel of the Amirante Passage (see Johnson and Damuth, 1979).  It 
   then takes the ship northwards to the edge of the Anton Brun bank from where a 
   section across the central portion of the passage will be done.  This section 
   repeats one of the Barton and Hill (1989) sections. 

3) There are three ways of moving around the Seychelles, 1) moving westward 
   into the Somali Basin and crossing the equator on the deep axis of the basin, 
   2) completing the section from the shallow topography on the northern edge of 
   the Seychelles, or 3) moving eastward around the Seychelles and crossing the 
   equator at approximately 57 E.  In order to save time the proposed course 
   crosses the bank.  According to the sailing directions this requires crossing 
   the bank edge south of 5 S.  Restrictions require that the ship use the 
   approaches to Mahe as depicted on DMA 61541. 

4) A cross equatorial section is to the east of the 1987 occupations of 
   Johnson (1990), Johnson et al. (1991a). This allows an investigation of their 
   suggested eastward deep water flow along the equator. 

5) Repeat occupation of the 1986-87 lines across the Carlsberg Ridge at 
   approximately 60 E.  On the Somali basin side this will provide a picture of 
   the representative nature of the broad deep flow along the Carlsberg from the 
   equator.  On the northern side of the ridge the section provides another 
   realization of the southeastward flow of waters in the southern Arabian basin.  
   The important question is whether the weak transports found on this section in 
   1987 SW monsoon (Johnson et al., 1991b) are typical of this season.  It is 
   hoped that repeat hydrography will allow at some time another look at the 
   stronger NE monsoon flow suggested in the 1986 cruise.  The WHP re-occupation 
   of this section is nicely complemented by the I1 section and German WOCE work 
   in the Owens fracture zone.  Finally, the properties along the northern flank 
   of the Carlsberg Ridge will be compared to I1 stations along the Chagos-
   Laccadive ridge at 10N to consider the possible addition of deep waters to the 
   Arabian Sea from the Central Indian basin to the east.

6) Occupation of a line along 65 E in the central Arabian basin will provide 
   a first deep realization of the extent of tilted density surfaces in the S.W. 
   monsoon.  The 1987 occupation suggests the monsoon effects are felt at least as 
   deep as 1200 m.  The strength of mid-ocean upwelling during a, hopefully, more 
   typical SW monsoon is also important in relationship to the monsoonal response 
   of the upper waters.  Finally the line will be closed into the Oman coast in 
   the proximity of Maseria Island.  This will provide a closed estimate of the 
   cross basin fluxes which are not available from earlier station data.  This 
   section is offset from the JGOFS line such that it cuts through a gap in the 
   Owens Ridge.  In agreement with JGOFS this will allow three synoptic sections 
   to be accomplished along the Oman coast during the SW monsoon.

7) A deep line of stations will be completed up the center of the Gulf of 
   Oman, including the distribution of properties in proximity to the Murray 
   Ridge.  The end of this line in the Arabian Basin corresponds to the center of 
   the oxygen minimum zone in the thermocline.  The coverage along the Murray 
   ridge allows a check on the suggested anticyclonic flow over this feature 
   (Qurishee, 1984).  A line of stations up the center of the Gulf of Oman and 
   then into the coast off Sohar provides a detailed investigation of the inflow 
   of Arabian (Persian) Gulf Water into the basin.  The final station in the 
   Straits of Hormuz is meant to further specify the Arabian Sea Water properties.  
   This station is placed in the deep trough between As Salamah wa Banatuh Island 
   and Musandam Peninsula.  Again this is in a restricted area for inshore dhow 
   traffic.  Therefore special permission must be obtained from Oman or the 
   station will have to be done off Jazirat Musandam.

Table C.2:  Parameters, contributing institutions and personnel 

University of Alaska		David Musgrave, Co-Chief Scientist
				(console, data checking) 

National Center for 		Scott Doney, Co-Chief Scientist 
Atmospheric Research 		(console, data checking) 

Scripps ODF CTD, Salts, 	Carl Mattson, Watchleader (Electronics)
Oxygen and Nutrients		Bob Williams, O2 (Data processing)
				John Boaz, Watchleader (Bottle Data Processing/O2) 
				Mary Johnson (CTD Processing)
				Craig Hallman (Salts/O2)
				Rhonda Kelly (Nuts)
				Stacey Morgan (Nuts)
				Piers Chapman (Salts)

University of Miami		Donald Olson, Chief Scientist
				Shery Zimmerman, Graduate Student (Salt)
				John Hargrove, Graduate Student (ADCP)
				Alexis Zubrow, REU Student, Harvard
				Kevin Sullivan (CFC)
				Craig Neill (CFC)
				Evan Howell (CFC, deck)
				Srinivasan Ashwanth (Tritium/helium)
				Donald Cucchiara (salts, sampling)

LODYC (U. of Hawaii)		Elodie Kestenare (ADCP)

University of Hawaii		Rolf Schottle (CO2)
				Angela Adams (CO2)
				Jennifer Phillips (CO2)
				Kelly Angeley (CO2)

Princeton			Tasha Zahn (C-14)

Observers			Sultan bin Rashed bin Ali Al-Rasbi
				Mohammed bin Khamis bin Saif Al-Muzaini

				Address for both:
				Ministry of Regional Municipalities
				and Environment 
				P.O. Box 323
				Muscat
				Oman PC 113

Preliminary Results:

WOCE WHP line I7N has just completed the portion of the leg south of the 
equator.  All operations are going well.  The following are some of the 
preliminary results for the Mascarene Basin and the region around the 
Seychelles.  The cruise track consisted of a line up the central Mascarene Basin 
and then a line into the western boundary on the Farquhar Ridge.  This segment 
in the northern Mascarene Basin angled northwest into the Anton Brun Bank 
cutting the deep western boundary current at a right angle.  The track then 
turned northeast across the Amirante Trench and the Amirante Ridge and then 
northeast to the Seychelles Bank.  An upward-tilting of isotherms below 3800 
dbar along the flank of the Farquhar Ridge indicated a northward flowing deep 
western boundary current that intensified within the 200 km of Anton Brun Bank.  
Within 500 km of the ridge, the transport below 3800 dbars was 3.0 Sv 
(northward) relative to 3800 dbars.  The transport in the 200 km closest to the 
ridge was 1.3 Sv (northward).  Some reversals in the station-pair transports 
occurred at distances greater than 200 km from the boundary.

There were four stations with bottom depths greater than 3800 m across the 
Amirante Trench.  The deep western boundary current was indicated by uplifted 
isotherms on the western side of the trench.  The total transport below 3800 
dbars was 1.6 Sv with a slight (0.2 Sv) southward flow in the last station pair 
on the eastern side of the trench.  These results are not significantly changed 
if the transport is taken below the 1.2 degree potential temperature using the 
pressure at the isotherm for the zero-velocity surface.  This result is quite 
similar to the Fieux and Swallow (1988) estimate of 0.8-2.05 Sv (relative to 
3800 dbars) and certainly less than Barton and Hill (1989) estimate of 3-5 Sv.  
The lowered ADCP gave evidence for the cores of these currents but is 
contaminated by barotropic tides to the extent that transports from limited 
current profiles are not feasible. 

Northeast of the Amirante Ridge there is a sudden change in deep water 
properties with the deep high oxygen, low silicate waters being absent.  The 
waters in the cul-de-sac between the ridge and the Seychelles Bank have 
definite northern properties that apparently arise from a flow through the 
passage between the two topographic features.  Another interesting feature in 
the deep water masses is the existence of a higher oxygen form of Indian Common 
Water along the northern blank of the Seychelles platform.  Again as in the 
cul-de-sac the trend to high oxygen, low silicate below the silicate maximum 
associated with circumpolar deep waters is absent.  The waters just above the 
silicate max, however, trend to higher oxygen on a set of stations between 
Seychelles and the equatorial wave guide. 

Equatorial currents extending from around 2.5 south northwards to 1.5 N. 
Surface currents were to the east at -.50 m/s and there was evidence of 
upwelling.  This is somewhat surprising given the winds and the season!  
Perhaps the current pattern is evidence of a wave or meander.  There was an 
undercurrent at approximately 175 m with a secondary current max of -.50 m/s. 
Deeper the flow was reversed to the east at mid-depth and then reversed back to 
the west near the bottom.  Both of these were a little less than -.10 m/s in 
the lowered ADCP. 

A deep southwestward flow of cold (<1.3 theta), oxygen rich (>3.7 ml/l) low 
silica (140 uM) water is observed just north of the Carlsberg ridge.  The 
transport below the depth of the 1.7 deg potential temperature surface is 2 Sv 
relative to a zero velocity surface at 1.7 deg theta.  A Somali Basin origin 
via the Owens fracture zone for this deep water is supported by the water mass 
properties and flow direction, though substantial modification must occur 
enroute.  North of the boundary current, the deep water profiles in the Arabian 
Basin are characterized by a low oxygen, high silica bottom boundary layer 
likely due to remineralization at the sediment water interface.  The mid-depth 
inflow or mixing of northern high silica, low oxygen water leads to a residual, 
local oxygen maximum approximately 350--500 m above the bottom at about 45.86 
sigma-4. 

Coming into the Omani coast east of Ras al Madraka we encountered three cool 
strips with shallowing mixed layers.  The first was at 14.5 N with a 0.5 C 
temperature drop and a 35 m shoaling in mixed layer.  This is south of the wind 
jet maximum that occurred at 15.5 north and had winds of only 13.5 m/s.  The 
next cool strip was at 16.5 N an involved a one degree step and a 45 m decrease 
in mixed layer depth.  This was followed by an increase in temperature and 
mixed layer followed by a 2 C drop at 17.5 N where the mixed layer went to 
around 25 m depth.  This was followed at around 19 N where we entered the 
coastal upwelling plume off Ras al Madraka.  Our lowest temperature there was 
22.5 C.  This seemed to be the same plume that R/V Thompson (JGOFS) surveyed to 
the west at the shelf end where it had 20 C water.  It seems that these 
offshore features are tied to open ocean upwelling.  They seem to be too far 
from any cape to be of coastal origin, but analysis of available AVHRR data 
will be required to verify this.  As per plans extensive work was carried out 
in the Gulf of Oman with three sections one across the mouth of the Gulf at Ras 
al Hadd and two into the Oman coast off Muscat and Sohar.  A final station was 
occupied just northeast of the Masandam peninsula where there is a deep region 
(approx. 200 m) between the traffic separation lanes and the inshore dhow lane.

Individual Group Reports:

Acoustic Doppler Current Profiling.
Preliminary Cruise Report (23 August 1995) - 

Acoustic Doppler Current Profiler Observations on I7N 
Peter Hacker and Eric Firing
University of Hawaii, SOEST
1000 Pope Road, MSB 312
Honolulu, HI 96822 USA

All data are to be considered preliminary at this time.  For information on the 
data contact:

Firing:		(808) 956-7894; efiring@soest.hawaii.edu
Hacker:		(808) 956-8689; hacker@soest.hawaii.edu
Hummon:		(808) 956-7307; jules@soest.hawaii.edu
Kestenare:	(808) 956-7099; elodie@soest.hawaii.edu 
FAX:		(808) 956-4104

Ocean velocity observations were taken on the WHP Indian Ocean Expedition line, 
I7N, using two acoustic Doppler current profiler (ADCP) systems and accurate 
navigation data.  The two systems are the hull-mounted ADCP and a lowered ADCP 
mounted on the rosette with the CTD.  The data were taken aboard the R/V KNORR 
from July 15, 1995 to August 23, 1995 between Port-Louis, Mauritius and Muscat, 
Oman.  The purpose of the observations was to document the upper ocean 
horizontal velocity structure along the cruise track, and to measure vertical 
profiles of the horizontal velocity components at the individual hydrographic 
stations.  The observations provide absolute velocity estimates including the 
ageostrophic component of the flow.  Figure 1* shows the cruise track and the 
near surface currents measured by the hull-mounted ADCP.

Hull-mounted ADCP:

The hull-mounted ADCP is part of the ship's equipment aboard the KNORR. The 
ADCP is a 150 kHz unit manufactured by RD Instruments. The instrument pings 
about once per second, and for most of the cruise the data were stored as 5-
minute averages or ensembles. The user-exit program, ue4, receives and stores 
the ADCP data along with both the P-code navigation data from the ship's 
Magnavox receiver and the Ashtech gps receiver positions. The P-code data are 
used as navigation for the ADCP processing. The ship gyro is providing heading 
information for vector averaging the ADCP data over the 5-minute ensembles. The 
user-exit program calculates and stores the heading offset based on the 
difference between the heading determination from the Ashtech receiver and from 
the ship gyro. The ADCP transducer is mounted at a depth of about 5 meters 
below the sea surface. 

As setup parameters, we used a blanking interval of 4 meters, a vertical pulse 
length of 16 meters, and a vertical bin size of 8 meters.  We used a 5 minute 
sampling interval for the entire cruise. 

Bottom tracking was activated during the shallow water transits near Port-
Louis, Seychelles Islands crossing, and along the coasts of Muscat.  For the 
processing of the ADCP data aboard ship, we used a rotation amplitude of 1.007, 
a rotation angle of -0.5 degrees (added to the gyro minus gps heading), and a 
time filter width of 0.0208 days (30 minutes).  Final editing and calibration 
of the ADCP data has not yet been done. 

A complete set of preliminary plots was generated during the cruise.  The plots 
consist of: vector plots with velocity averaged over several depth intervals, 
and over a tenth or a twentieth of degrees in spatial grid; and contour plots 
of u (positive east) and v (positive north) typically averaged over 0.1 degree 
of longitude or latitude, depending on the track.  The velocity was measured 
from a depth of 21 meters to a depth of about 300 to 400 meters, typically, 
during the first part of the cruise.  During the last twenty days (in Arabian 
sea), the depth range decreased to about 150 to 250 meters during the nighttime 
due to a strong diurnal variability in scattering.

Lowered ADCP:

The second ADCP system is the lowered ADCP (LADCP), which was mounted to the 
rosette system with the CTD.  The LADCP yields vertical profiles of horizontal 
velocity components from near the ocean surface to near the bottom.  The unit 
is a broadband, self-contained 150 kHz system manufactured by RD Instruments, 
model BBCS 150, serial no. 1246.  We used single ping ensembles.  Vertical 
shear of horizontal velocity was obtained from each ping.  These shear 
estimates were vertically binned and averaged for each cast.  By combining the 
measured velocity of the ocean with respect to the instrument, the measured 
vertical shear, and accurate shipboard navigation at the start and end of the 
station, absolute velocity profiles are obtained (Fisher and Visbeck, 1993).  
Depth is obtained by integrating the vertical velocity component; a better 
estimate of the depth coordinate will be available after final processing of 
the data together with the CTD profile data.  The shipboard processing results 
in vertical profiles of u and v velocity components, from a depth of 60 meters 
to near the ocean bottom in 16 meter intervals.  These data have been computer 
contoured to produce preliminary plots for analysis and diagnosis. 

CTD casts were made at stations 708-856 on the I7N cruise.  LADCP casts were 
made at all stations except: stations 718 to 719 (a fuse had blown inside the 
instrument), station 720 (data have not been recovered, a problem linked to the 
previous one) and stations 855-856 (shallow water).  The deep casts often have 
noise problems below 3000 meters or so due to poor instrument range and 
interference from the return of the previous ping. 

Navigation:

The ship used a Magnavox receiver for navigation, with data coming in at once 
every two seconds.  We have stored this once every two seconds data for the 
entire cruise.  We also decimated this once every two seconds data by a factor 
of 10 to 20-second intervals and stored these processed files as daily matlab 
files of latitude, longitude and time.

The Ashtech receiver uses a four antennae array to measure position and 
attitude.  The heading estimate was used with the gyro to provide a heading 
correction for the ADCP ensembles.  The Ashtech data was stored by the ADCP 
user-exit program along with the ADCP data. 

References:

Fisher, J. and M. Visbeck, 1993.  Deep velocity profiling with self-contained 
  ADCPs; J. Atmos. Oceanic Technol., 10, 764-773.  

ALACE Float Deployments:

Eleven ALACE floats were deployed as part of the program.  These are ballasted 
to a nominal depth between 900 and 1000 m.  These units have a planned lifetime 
of five years.  The launch positions for these are:

Number	Deployment Time	  Position	Station

509	16-07-95 0842 Z	18 01.17 S	710	
			55 00.17 E
475	17-07-95 1806 Z	15 05.11 S	715	
			55 00.48 E
499	19-07-95 0226 Z	12 14.99 S 	720	
			52 19.18 E
510T	20-07-95 2305 Z	10 00.02 S 	727	
			52 19.18 E
511T 	24-07-95 0705 Z	07 30.93 S	741
			53 37.73 E
512T	26-07-95 2129 Z	03 14.94 S 	750
			56 00.44 E
513T	28-07-95 0944 Z	00 52.10 S	756
			57 14.65 E
514T	29-07-95 2139 Z	00 55.99 N	762
			57 17.60 E
515T	01-08-95 0223 Z	03 35.06 N	769
			58 47.60 E
520T	03-08-95 0359 Z	06 23.64 N	776
			61 21.33 E
531T	06-08-95 0500 Z	10 32.42 N	786
			64 39.79 E

The launches cover the southern end of the I7N track up to a point just north 
of the Carlsberg Ridge.  Deployments were accomplished earlier north of this 
from JGOFS cruises.  The addition of the T on the serial number above indicates 
a temperature profiling float.  

The floats nominal depth range encompasses primarily the upper levels of the 
Indian Ocean Common Water as depicted by an oxygen minimum and either salinity 
maximum (floats 475, 499, 510, 512 and 515) or in a region of rising salinity 
below the Antarctic Intermediate Water layer (floats 509, 511, 513) or the more 
saline Red Sea water in the north (floats 520 and 531).  In particular ALACE 
511 is deployed in common waters moving southward along the Armiante Ridge into 
the northern-most reaches of the Mascarene Basin.  All of the floats are one to 
several hundred meters below the 27.2 potential density surface along which the 
Red Sea and Antarctic Intermediate Waters mix.

CO2 Group Summary-I7N:
			Alkalinity	Total CO2

Total Samples Ran	2805		2805
From Rosette
(Including Replicates)

Replicates		216		216
CRMs			74		150
Surface Sea Water	74		----

Comments: Overall the data set appears very good from looking at the data 
quality indicators.  As a general guideline for practical data quality 
objectives we are looking for approximately +/- 1.0 uM/Kg for DIC and +/-3.0 
uM/Kg.  The entire data set falls within or near to those objectives.  We 
encountered very few instrument difficulties during the cruise.  Most every 
instrument problem encountered was fixed prior to analysis of any project 
samples.  I expect to have very little data flagged as uncertain for the final 
WOCE deliverable.  In general, the instrumentation is in decent working order 
and there are adequate consumables for the next group's leg.  In addition, I 
will forward you the Replicate/CRM statistics I have already sent back to our 
laboratory.

Statistics for the DIC:
(All values are in uM/Kg. n= number of samples, x=mean, SD=std dev.)

CRM's:

SOMMA1		Batch 27 n = 10  x = 1985.27  SD = 1.06
		Batch 26 n = 53  x = 1976.89  SD = 1.34
		Batch 23 n = 8  x = 1991.43  SD = 1.11

SOMMA2		Batch 27 n = 10  x = 1985.08  SD = 0.77
		Batch 26 n = 56  x = 1976.04  SD = 0.87
		Batch 23 n = 8  x = 1990.24  SD = 1.11

Duplicates:

SOMMA1		n= 104  mean of diff.= .866  SD of diff.= .728
SOMMA2		n=  97  mean of diff.= 1.03  SD of diff.= .833

Alkalinity statistics.  All values in uM/Kg:

CRMS:

Cell 2		CRM Batch#26  n=29  mean=2185.21  S.D.=3.838
		minus outliers  n=27  mean=2184.493 S.D.=2.862

		CRM Batch#27  n=4  mean=2221.35  S.D.=2.110
		No outliers

 		CRM Batch #23  n=3  mean=2223.133  S.D.=0.946
		No outliers

Cell 13 	CRM Batch #26  n=27  mean=2181.948  S.D.=3.192
		minus outliers  n=25  mean=2181.34  S.D.=2.448

		CRM Batch #27  n=3  mean=2219.733  S.D.=2.040
		No outliers

		CRM Batch #23  n=2  mean=2219.9  S.D.=0.4
		No outliers

ALL		CRM Batch #26  n=56  mean=2183.638  S.D.=3.899
		minus outliers  n=52  mean=2183.051  S.D.=3.076

		CRM Batch #27  n=7  mean=2220.657  S.D.=2.229
		No outliers

		CRM Batch #23   n=5  mean=2221.84  S.D.=1.764

Surface Water Samples:

Cell 2		First Carboy  n=19  mean=2334.197  S.D.=5.412
		No outliers

		Second Carboy  n=15  mean=2354.82  S.D.=7.588
		minus outliers  n=14  mean=2353.0  .D.=3.465

Cell13		First Carboy  n=21  mean=2326.189  S.D.=4.553
		minus outliers  n=18  mean=2326.815  S.D.=2.640

		Second Carboy  n=12  mean=2350.342  S.D.=5.721
		No outliers greater than 2 sigma

ALL		First Carboy  n=40  mean=2329.993  S.D.=6.386
		minus outliers  n=37  mean=2339.403  S.D.=5.334

		Second Carboy  n=27  mean=2352.83  S.D.=7.175
		minus outliers  n=26  mean=2349.944  S.D.=4.83

Replicates:

Cell 2 		n=63  mean of difference=2.270  S.D. of diff=2.566
 		minus outliers n=55  mean of difference=1.430  
		S.D. of diff=1.213

Cell 13	n=57	mean of difference=2.184  S.D. of diff=3.289
 		minus outliers n=53  mean of difference=1.430
		S.D. of diff=1.581

Inter-Cell Comparison:

		n=77  mean of difference=3.166  S.D. of diff=4.130
 		minus outliers n=69  mean of difference=1.93
		S.D. of diff=1.704

CFC Sampling:

Chloroflurocarbon Sampling on I7N

As part of the suite of transient tracers sampled on WOCE I7N 
chloroflourocarbons eleven and twelve (CFC-11 and CFC-12) were analyzed from 
rosette casts.  These anthropogenic gases have atmospheric histories dating 
from the middle of this century.  The concentrations of these trace gases 
provide a clue to the time scales involved with atmospherically derived gases 
introduced into the ocean.  This process, typically referred to as ventilation, 
is of interest in relation to the uptake of carbon dioxide by the ocean and the 
balance between the introduction of oxygen in the surface layers to its 
consumption by respiration of organic matter in the ocean interior.  The latter 
is of particular interest because of the pronounced oxygen minimum zones found 
in the Arabian Sea. 

Water samples were drawn with glass syringes and analyzed for CFC-11 and CFC-12 
by two technicians standing complementary 12-hour watches.  A total of 2,834 
water samples were drawn at 146 of 149 stations.  The ability to sample so many 
stations, especially across the equator, was greatly due to the decision to 
steam at a speed less than maximum between those stations.  The extra time 
allowed the samples drawn on one station to be processed before the next cast 
arrived on deck.  Enough samples were drawn on a cast to cover the CFC signal 
plus several bottles in deeper CFC-free water. 

Three stations were utilized to obtain additional bottle blank information.  On 
these stations, the closing of the bottles was started at bottle 15, 19, or 28 
and continued around the rest of the rosette.  This alternate firing procedure 
closed the bottles that normally sampled upper waters (118-136) in deep, CFC-
free waters.  These casts plus the deeper routine sampling will provide the 
final bottle blank values that will be applied. 

The CFC analyses were done via a custom-built extraction system from Dr. Rana 
Fine's group at the University of Miami.  The extraction system employs a 
purge-and-trap process to remove the dissolved gases from the water collected 
in glass syringes.  These gases are then separated and measured with an 
electron-capture gas chromatograph.  The analytical system operated almost 
constantly with little loss of time or samples.  Throughout the cruise, the 
analytical blanks were zero or near zero (averaging <0.003 pM CFC-11/kg and 
<0.001 pM CFC-12/kg water).  The precision of the duplicate water analyses was 
generally 1% or better.  The changes in sensitivity of the electron-capture 
detector were compensated for with regular standard analyses.  The peaks in the 
chromatograms were integrated automatically with a PC-based data acquisition 
package.  Due to the very busy sampling and analyses schedule the smallest 
peaks were not reintegrated under manual software control.  This part of the 
post-acquisition processing will be done after the cruise.  Preliminary results 
were compiled on disk and transferred to the archiving computer onboard.  
Vertical profiles were printed and examined as a check on data integrity.

Air analyses were also done as time permitted throughout the cruise. 53 samples 
were taken via a diaphragm pump with a inlet at the bow.  The atmospheric 
concentrations were close to 513 part per trillion for CFC-12 and 268 parts per 
trillion CFC-11.  The atmospheric values were slightly different on either side 
of the equator.  These are preliminary values, as are the water concentrations.  
Extensive post-cruise processing of the data will change the values slightly.

Contact: 
Dr. Rana Fine
MAC/MPO University of Miami
4600 Rickenbacker Cswy.
(305) 361-4722
(rana@longan.rsmas.miami.edu).   

-------------------------------------------------------------------------------
IMET DATA STATUS REPORT

Cruise:			I7 (Knorr 145-10)
Dates:			15 July - 23 August, 1995
Location:		Port Louis, Mauritius to Muscat, Oman
Chief Scientist:	Donald Olson

Equipment in Use:
The following IMET sensors were installed and in use during I7.

	Type				Serial Number	Label

	Air Temperature			119		TMP
	Barometric Pressure		118		BPR
	Precipitation 			113		PRC
	Relative Humidity 		115		HRH
	Sea Surface Temperature		108		SST
	Short Wave Radiation		003		SWR
	Wind Speed and Direction	004		WND 

Data:

The data was logged to ASCII text files, one per day.  With this document you 
have received complete copies of the data on exabyte tape.  The tape contains a 
single tar archive which contains one file per day.  The files are named 
YYMMDD.dat, where YYMMDD is the year, month, and day which is covered in the 
file.  Logging began on July 15th at 04:06UTC, and ended on August 23rd at 
10:55UTC. 

On August 16th at 00:00UTC, GPS course and speed over ground information was 
added to the items recorded in these files.  Course and speed over ground 
information is not included for times prior to 08/16-00:00. 
The following data items were recorded once per minute during this cruise:

 	Item Name	Description

	CTIME		Computer time
	GP20P_TP	Port GPS 200 time & position
	GP20S_GC	Stbd GPS 200 course over ground
	GP20S_GS	Stbd GPS 200 speed over ground
	GP20S_TP	Stbd GPS 200 time & position
	GYRO		Ship's heading (Gyro syncro)
	IMET_AIR	Air temperature (degrees C)
	IMET_BPR	Barometric pressure (millibars)
	IMET_HUM	Relative humidity (percent)
	IMET_PRC	Precipitation (millimeters)
	IMET_SEA	Sea surface temp (degrees C)
	IMET_SWR	Short wave radiation (watts/sq m)
	IMET_WNC	Compass reading (degrees) [NOT CALIBRATED]
	IMET_WND	Wind direction (ship relative)
	IMET_WNS	Wind speed (m/s, ship relative)
	SPDLOG		Ship's speed (EDO Speedlog)
	SSCND		Sea surface conductivity (mmho/cm)
	SSTMP		Sea surface temperature (C)

There were a few large gaps in the data during the cruise.  Any gap longer than 
15 minutes while under way, and any gap longer than one hour while on station 
are listed below, with a short explanation of each.  If only a subset of the 
data items are missing for the period indicated, the missing items will be 
listed along with the notes.  In the table below OS stands for on station, and 
UW stands for under way. 

Date		Start	Stop	Length	W/OS 	Notes	(Including data affected)	
07/22		11:22	12:00	38 min.	UW	Data Logging Computer Failure [all data]	
07/23		02:07	02:23	15 min.	UW	Data Logging Computer Failure [all data]	
08/05-06	22:54	04:04	5.2 hr.	Both	Data Logging Computer Failure [all data]
08/19		05:56	06:13	17 min.	UW	Interface Device Failure [GYRO] *	
08/16-19	03:19	07:30	3.2 day	Both	Interface Device Failure [SPDLOG] *
08/21		02:27	03:02	35 min.	UW	Device Configuration Change [GP20P_TP]	

* The interface device which provides both gyro and speedlog data was 
inoperable for 3.2 days.  Gyro information every five minutes was recovered 
from ADCP data files and merged into this data set. 

--------------------------------------------------------------------------------
World Ocean Circulation Experiment
Indian Ocean I7N
R/V Knorr Voyage 145/10

ODF Operations Preliminary Cruise Report
August 23, 1995

C.W. Mattson
Oceanographic Data Facility
Scripps Institution of Oceanography
La Jolla, Ca. 92093-0214

Summary:

A hydrographic survey consisting of 149 CTD/Rosette stations were performed on 
a South to North cruise track along  54-65 E from 20 S to 26 N in the 
Southwestern Indian Ocean through the Arabian Sea to the last station in the 
Strait of Hormuz.  The  R/V  Knorr  departed  Port  Louis, Mauritius on 15 July 
1995.  The first station started at number 708.  The last station was number 
856.  During most stations all 36 rosette bottles were tripped for a total of 
5117 water sampler  bottles  for the cruise.  Salinity, dissolved oxygen and 
nutrient measurements were taken at all stations from every bottle that  was 
tripped.  The cruise ended in Matrah, Oman on 23 August 1995. Eleven ALACE 
floats were deployed during the first half of the cruise.

Scientific Personnel

Name			Title			Affiliation		Duties	
Donald B.Olson		Professor		RSMAS			Chief Scientist
David L. Musgrave	Assoc Professor		U. Alaska-FB		Co-PI/Btl Data/Rosette
Scott Doney		Scientist I		NCAR			Co-PI/Btl Data/Rosette	
Carl W. Mattson		Pr Electronic Tech	STS/ODF			TIC/Watch Leader/ET/Rosette	
John Boaz		Marine Tech		STS/ODF			Watch Leader/O2/Rosette/Btl data
Stacey R. Morgan	SRA			STS/ODF			Nutrients	
Rhonda M. Kelly		SRA			STS/ODF			Nutrients	
Craig M. Hallman	SRA			STS/ODF			Oxygen/Salt/Rosette
Robert T. Williams	Programmer Analyst	STS/ODF			Oxygen/Rosette/Btl data	
Mary C. Johnson		SRA			STS/ODF			CTD data Processing	
Evan A. Howell		Grad Student		RSMAS			Ctd Console/Rosette/CFC
Alexis A.S. Zubrow	UnderGrad Student	RSMAS			Ctd Console/Rosette	
Shery Zimmerman		Grad Student		RSMAS			Ctd Console/Rosette
Donald D. Cucchiara	Marine Tech		RSMAS			Salt/Rosette
Piers Chapman		Director US WOCE	TAMU			Salt/Rosette
Elodie Kestenare				JIMAR			LADCP/ADCP	
John T. Hargrove	Grad Student		RSMAS			LADCP/ADCP	
Rolf G. Schottle	Research Assoc III	U. Hawaii		TCO2/Alkalinity	
Kelly J. Angeley	Analytic Chemist	U. Hawaii		TCO2/Alkalinity	
Angela K. Adams		Grad Student		U. Hawaii		TCO2/Alkalinity	
Jennifer A. Phillips	UnderGrad Student	U. Hawaii		TCO2/Alkalinity
Tasha A. Zahn		Lab Assistant		PU/OTL			C14/Ra-228/PCO	
Kevin F. Sullivan	Marine Tech Spec	RSMAS			CFC
Craig Neill		Consultant		RSMAS			CFC
Ashwanth Srinivasan	Grad Student		RSMAS			He/Tr	
Ken Feldman		SSG Tech		WHOI			Res Tech	
Mohammed Al-Muzaini				MRME			OMAN Observer
Sultan Al-Rashi		Chemist			MRME			OMAN Observer/TCo2

Scientific Personnel WOCE I7N

1.  Programs

Table 1.0 Principal Programs of WOCE I7N

Analysis			Institution	Principal Investigator
Basic Hydrophogy (Salinity,	SIO		James H. Swift
O2, Nutrients, CTD)
CFC				RSMAS		Rana Fine
He/Tr				RSMAS		Zafer Top
AMS 14C and Ra-228		Princeton	Robert Key
TCO2 & Alkalinity		U. Hawaii	C. Winn
TCO2				SIO		Charles Keeling
Barium				OSU		Kelly Faulkner
Transmisometer			TAMU		Wilf Gardner
ADCP and LADCP			U. Hawaii	Erik Firing
ALACE Floats			SIO		Russ Davis
UW PCO2				Princeton	Robert Key
UW Air Chemistry		U. Hawaii	C. Winn
UW Meteorology (IMET)		WHOI		B. Walden
UW Thermosalinograph		WHOI

The principal programs of I7N are shown in Table 1.0.  The basic hydrography 
program is described in detail in this report.

1.1.  Basic Hydrography Program

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.  Rosette casts at 149 stations were made to 
within 10 meters of the bottom.  No major problems were encountered during any 
phase of the operation.  The resulting data set met and in many cases exceeded 
WHP specifications.  The distribution of samples is illustrated in figures 
1.1.0* and 1.1.1*.

Figure 1.1.0* Sample distribution, stations 709-786 (WOCE I7N).

Figure 1.1.1* Sample distribution stations 787-856.

2.  Description of Measurement Techniques

2.1.  Water Sampling Package

Hydrographic (rosette) casts were performed with a 36-place 10-liter rosette 
system consisting of a 36-bottle rosette frame (ODF), a 36-place pylon (General 
Oceanics 1016) and 36 10-liter PVC bottles (ODF).  Underwater electronic 
components consisted of an ODF-modified NBIS Mark III CTD and associated 
sensors, SeaTech Transmisometer, RDI LADCP, Benthos altimeter and Benthos 
pinger.  The CTD was mounted  horizontally along the bottom of the rosette 
frame, with the transmissometer, a dissolved oxygen and a secondary PRT sensor 
deployed alongside.  The LADCP was vertically-mounted to the frame inside the 
bottle rings.  The  Benthos altimeter provided distance-above-bottom in the CTD 
data stream.  The Benthos pinger was monitored during a cast with a precision 
depth recorder (PDR) in the ship's laboratory.  The rosette system was 
suspended from a three-conductor electromechanical (EM) cable.  Power to the 
CTD and pylon was provided through the cable from the ship.  Separate 
conductors were used for the CTD and pylon signals.

Each rosette cast was performed to within 10 meters of the bottom, unless the 
bottom returns from both the pinger and altimeter were extremely poor.  Bottles 
on the rosette, each identified with a unique serial number.  Usually these 
numbers corresponded to the pylon tripping sequence 1-36 with the first bottle 
tripped being bottle serial #1.  Bottles serial numbered 1-36 were used on all 
casts except during stations 719-721 when bottle 37 was used in place of bottle 
29.  Bottle 29 was reinstalled prior to sta 722.  Averages of CTD data 
corresponding to the time of bottle closure were associated with the bottle 
data during a cast.  Pressure, depth, temperature, salinity and  density were  
immediately available to facilitate examination and quality control of the 
bottle data as the sampling and laboratory analyses progressed.

The deck watch prepared the rosette approximately 45 minutes prior to a cast.  
All valves, vents and lanyards were checked for proper orientation.  The 
bottles were cocked and all hardware and connections rechecked.  Upon arrival 
on station, time, position and bottom depth were logged and the deployment 
begun.  The rosette was moved from the starboard hangar into position under a 
projecting boom using an air-powered cart on tracks.  Two stabilizing tag lines 
were threaded through rings on the frame.  CTD sensor covers were removed and 
the pinger turned-on.  Once the CTD acquisition and control system in the 
ship's laboratory had been initiated by the console operator and the CTD and 
pylon had passed their diagnostics, the winch operator would raise the package 
and extend the boom over the side of the ship.  The package was then lowered 
into the water, the tag lines removed and the console operator notified by 
radio that the rosette was at the surface.

At the end of the cast while the rosette was at the surface two air tuggers 
spun with tag lines terminating in large snap hooks were manipulated on long 
poles by the deck watch to snag recovery rods on the rosette frame.  The 
package was then lifted out of the water under tension from the tag lines, the 
boom retracted, and the rosette lowered onto the cart.  Sensor covers were 
replaced, the pinger turned-off and the cart with the rosette moved into the 
hangar for sampling.  A detailed examination of the bottles and rosette would 
occur before samples were taken, and any extraordinary situations  or 
circumstances noted on the sample log for the cast.

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

The R/V Knorr portside CTD Markey winch was used on stations 708-856.   A new 
ctd wire was installed on this winch during a port stop in Durban during the 
previous leg (I5W/I4).  New ctd wire was installed on stbd winch at the start 
of the leg in Port Louis.  This wire checked out ok and was available as a 
backup.  The stbd winch was never used on I7N.

2.2.  Underwater Electronics Packages

CTD data were collected with a modified NBIS Mark III CTD (ODF CTD #1).  This 
instrument provided pressure, temperature, conductivity and dissolved O2 
channels, and additionally measured a second temperature (FSI temperature 
module) as a calibration check.  The pressure sensor is a Paine model 211-35-
440-05 strain gage 0-8850 PSI transducer.  The primary temperature sensor is a 
Rosemount  model 171BJ.  Other data channels included elapsed-time, an 
altimeter, several power supply voltages and a Transmisometer.  The instrument 
supplied a standard 15-byte NBIS-format data stream at a data rate of 25 fps.  
Modifications to the instrument included revised pressure and dissolved O2 
sensor mountings; ODF-designed sensor interfaces for O2, FSI PRT and the 
SeaTech Transmisometer; implementation of 8-bit and 16-bit multiplexer 
channels; an elapsed-time channel; instrument id in the polarity byte and power 
supply voltages channels.

The CTD pressure sensor mounting had been modified to reduce the dynamic 
thermal effects on pressure.  The sensor was attached to a section of coiled 
stainless-steel tubing threaded into the end-cap pressure port.  The transducer 
was also insulated.  The NBIS temperature compensation circuit on the pressure 
interface was disabled; all thermal response characteristics were modeled and 
corrected in software.

The O2 sensor was deployed in a pressure-compensated holder assembly mounted 
separately on the rosette frame and connected to the CTD by an underwater 
cable.  The O2 sensor interface was designed and built by ODF using an off-the-
shelf 12-bit A/D converter.  The Transmisometer interface was a similar design.

Although the secondary temperature sensor was located within 1 meter of the CTD 
conductivity sensor, it was not sufficiently close to calculate coherent 
salinities.  It was used as a secondary temperature calibration reference 
rather than as a redundant sensor, with the intent of eliminating the use of 
DSRTs as calibration checks.  Due to a previously detected calibration drift in 
this sensor during the I9 leg, one rack of electronic DSRTs was employed anyway 
as an additional check.

Standard CTD maintenance procedures included soaking the conductivity and O2 
sensors in distilled water between casts to maintain sensor stability, and 
protecting the CTD from exposure to direct sunlight or wind to maintain an 
equilibrated internal temperature.

ODF CTD #1 was used throughout the leg with the exception of two casts.  The 
first such cast, was during a test cast designated station 888 cast 88.  CTD#1 
was replaced with an FSI ICTD for testing purposes only.  This happened after 
station 747 at the same position as station 746.  This data was not used or 
reported for WOCE purposes.  The second occasion was on station 841 cast 2, 
when the MKIII CTD was again replaced with the FSI ICTD.  This occurred during 
the simultaneous casts conducted with the JGOFS rosette on the R/V Thompson.  
This cast was done to test and check the FSI ICTD and compare the data set with 
the MKIII.  On August 19 the R/V Knorr rendezvoused with the R/V Thompson at 
WOCE station 841 (JGOFS station 2).  The JGOFS and WOCE rosettes were 
simultaneously deployed for two casts each.  CTD#1 was used on cast 1.

The General Oceanics 1016 36-place pylon provided generally reliable operation 
and positive confirmation of all except 7 bottle trip attempts.  The General 
Oceanics pylon deck unit was not used.  Instead, an ODF-built deck unit and 
external power supply were employed.  The pylon emits a confirmation message 
containing its current notion of bottle trip position, an invaluable aid in 
sorting out mis-trips.

2.3.  Navigation and Bathymetry Data Acquisition

Navigation data was acquired from the ship's Trimbal GPS receiver via RS-232.  
It was logged automatically at one-minute intervals by one of the Sun 
Sparcstations.  Underway bathymetry was logged manually from the ship's 12 khz 
Raytheon PDR at five-minute intervals, then merged with the navigation data to 
provide a time-series of underway position, course, speed and bathymetry data.  
These data were used for all station positions, PDR depths, and for bathymetry 
on vertical sections [Cart80].

2.4.  CTD Laboratory Calibration Procedures

Pre-cruise pressure and temperature calibrations were performed on CTD #1 at 
the SIO/ODF Calibration Facility (La Jolla) in December, 1994, immediately 
prior to WOCE I9N.  This was the fifth consecutive Indian Ocean leg for this 
CTD (ODF  CTD #1).  CTD#1 is being shipped back to the ODF calibration 
laboratory for the post-cruise pressure and temperature calibration.  These 
calibration data will be compared with the pre-cruise calibration to determine 
if any changes occurred.  These data will aid in the cruise data post 
processing stage.

2.5.  CTD Shipboard Calibration Procedures

CTD Pressure and Temperature:
ODF used three independent methods to check for temperature or pressure 
instability during the course of the cruise.  First, Primary  temperature  as 
checked by comparing it to the secondary PRT sensor.  Two different temperature 
probes were used for the secondary PRT sensor.  The first such sensor (FSI OTM 
#1322) experienced a drift  of -0.008C during I9N, but had stabilized to a 
constant offset during I8N and I3.  This offset was noted to be 0.010C at the  
beginning of this leg and remained so throughout the leg.  The spare sensor 
(FSI OTM #1321) was installed in place of #1322 at the start of sta 722.  This 
OTM indicated 0.000C offset while it was used and working poperly, however, 
this OTM would intermittently cut in and out.  OTM #1322 was reinstalled at the 
start of sta 788.  FSI OTM #1322 was  used on stations 708-721, 788-856.  FSI 
OTM #1321 was used on stations 722-787.  The data from both secondary probes 
indicated  that no temperature shift occurred in the primary temperature 
channel.  Pressure was checked during a port stop at the beginning of the 
previous I4/I5W leg.  A Paroscientific Digi-Quartz secondary pressure reference 
was used as  a  pressure calibration transfer standard.  No shifts in the CTD 
pressure calibration were indicated.

Second, an additional check on temperature and pressure was made by using 
DSRT's.  One rack of digital SIS DSRT's was used on selected stations.  Each 
rack contained two thermometers and one pressure meter.  These measurements 
indicated no shifts in CTD temperature or pressure calibrations.

Third, pressure and temperature shifts during a cruise can be detected based on 
the conductivity calibration.  These conductivity checks indicated there were 
no significant shifts in the CTD pressure or temperature during this leg.

While in the Gulf of Oman, sea surface temperatures sometimes exceeded 30 Deg 
C.  On several stations the sea surface temperature exceeded the upper limit of 
the primary temperature on CTD #1.  This limit was 31.255 Deg C.  The  
secondary sensor remained in range.  The temperature from the secondary sensor 
was used for bottle data  calculations.  The station numbers that were affected 
by high sea surface temperatures were 845 and 852-856.

Conductivity:
The CTD rosette trip pressure and temperature were used with the bottle 
salinity to calculate a bottle conductivity.  Differences between the bottle 
and CTD conductivities were then used to derive a conductivity correction as a 
linear function of conductivity.  Bottle salinity analysis is discussed in 
section 2.10.

CTD Dissolved Oxygen:
A new CTD O2 sensor (#5-01-10) was installed before the leg began and was used 
throughout the leg.  There are a number of problems with the response 
characteristics of the Sensormedics O2 sensor used in the NBIS Mark III CTD, 
the major ones being a secondary thermal response and a sensitivity to 
profiling velocity.  Because of these problems, CTD rosette trip data are 
indirectly calibrated to O2 check samples.  Down-cast CTD O2 data are derived 
by matching the up-cast rosette trips along isopycnal surfaces.  The 
differences between CTD O2 modeled from these derived values and check samples 
are then minimized using a non-linear least-squares fitting procedure.  The 
general form of the ODF O2 conversion equation follows  Brown  and Morrison 
[Brow 78] and Millard [Mill 82], [Owen 85].  Oxygen sample analysis is 
discussed in section 2.11.

2.6.  CTD Data Acquisition, Processing and Control System

The CTD data acquisition, processing and control system consisted of Sun 
SPARCstation LX computer workstation, ODF-built CTD and pylon deck units, CTD 
and pylon power supplies and a VCR recorder for real-time analog backup 
recording of the sea cable signal.  The Sun system  consisted of a color 
display with track-ball and keyboard (the CTD console), 18 RS-232 ports, 2.5 GB 
disk and 8-mm cartridge tape.  Two other Sun LX systems were networked to the 
data acquisition system, as well as to the rest of the networked computers 
aboard the Knorr.  These systems were available for real-time CTD data display 
as well as providing hydrographic data management and backup.  Two HP 1200C 
color ink jet printers provided hardcopy from any of the workstations.

The CTD FSK signal was demodulated and converted to a 9600 baud RS-232C binary 
data stream by the CTD deck unit.  This data stream was fed to the Sun 
SPARCstation.  The pylon deck unit was also connected to the Sun through a bi-
directional 300 baud serial line, allowing rosette trips to be initiated and 
confirmed through the 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 data displays, navigation, winch 
and rosette trip displays.

The  CTD data acquisition, processing and control system was prepared by the 
console watch a few minutes before a 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 performed by pointing and 
clicking a trackball cursor on the display at pictures representing  functions 
to perform.  The system would then present the operator with a short dialog 
prompting with automatically-generated choices that could either be accepted as 
default or overridden.  The operator was instructed to turn on the CTD and 
pylon power supplies, then to examine a real-time CTD data display on the 
screen for stable voltages from the underwater unit.  Once this was 
accomplished, the data acquisition and processing was begun and a time and 
position automatically associated with the beginning of the cast.  A backup 
analog recording of the CTD signal was made on a VCR tape, which was started at 
the same time as the acquisition.  A rosette trip display and pylon control 
window then 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, the deck watch leader provided 
the winch operator with a target depth (wire-out) and lowering rate (normally 
60 meters/minute for this package).  The package would then begin its descent.

The console operator would examine the processed CTD data during descent via 
interactive plot windows on the display, which could also be initiated from 
other workstations on the network.  Additionally, the operator would decide 
where to trip bottles on the up-cast, noting this on the console log.

The rosette distance above bottom (DAB) was monitored on the PDR by the deck 
watch leader.  The rosette mounted pinger would transmit a ping that would be 
displayed on the ship's PDR system that indicated the rosette DAB.  At 
approximately 100 meters above the bottom the altimeter would normally begin 
signaling a bottom return on the console.  The winch displays and altimeter 
readout allowed the deck watch leader to refine the target depth relayed to the 
winch operator and safely approach to within 10 meters of the bottom.

Bottles would be tripped by pointing the console trackball cursor at a graphic 
firing control and clicking a button.  The data acquisition system would 
respond 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 would then direct the winch operator to the next bottle stop.  The 
console operator was also responsible for generating the sample log for the 
cast.

After the last bottle was tripped, the console operator would inform the deck 
watch that it was ok to bring the rosette on deck.  Once on deck, the console 
operator would terminate the data acquisition and turn off the CTD, pylon and 
VCR recording.  The VCR tape was filed.  Frequently the console operator would 
also bring the sample log to the rosette room and serve as the sample cop.

2.7.  CTD Data Processing

ODF CTD processing software consists of some 35-odd programs running under the 
Unix 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 specific channels according to specified filtering criteria.
* Apply sensor or instrument-specific response-correction models.
* Provide periodic averages of the channels corresponding to the output time-
  series interval.
* 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 a number of various ways.  Channels can be additionally 
filtered.  A time-series can be transformed into a pressure-series, or a longer 
interval time-series.  Calibration corrections to 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 real-time, 
providing calibrated, processed data for interactive plotting and reporting 
during a cast.  The 25 hz data from the CTD were filtered, response-corrected 
and averaged to a 2 hz time-series.  Sensor correction and calibration models 
were applied to pressure,  temperature, conductivity and O2.  Rosette trip data 
were extracted from this time-series in response to trip initiation and 
confirmation signals.  The calibrated 2 hz time-series data were stored on disk 
(as was the 25 hz raw data) 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 2.0 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 TS 
comparisons with adjacent stations.  The CTD dissolved O2 sensor was calibrated 
to check-sample data.

As noted earlier in this report, the seawater temperatures in the Gulf of Oman 
exceeded the capacity of the primary CTD temperature sensor on stations 845 and 
852-856.  Only the up-cast data were affected on station 845, so the down-cast 
data are complete.  The other 5 casts were affected on both down- and up-casts.  
The off-scale data on these casts were eliminated by starting the CTD pressure-
series from the pressure of the first on-scale temperature.

An attempt was made to re-average the off-scale casts using the secondary 
temperature sensor (PRT2 - an FSI sensor with a greater range), which was 
located about 3-4 inches away from the primary sensor.  The data were noisy 
because PRT2 and the conductivity sensor were not measuring the same water at 
the same time, so they did not correlate well enough to generate acceptable 
salinity data.  The PRT1 temperature data were reported with the final data.  
The PRT2-averaged data were used for generating temperatures to report with 
bottle data; the average PRT1-PRT2 difference at surface trips was .005 degrees 
C for the on-scale casts from stations 846 through 851.  Except for station 
845, differences between CTD and bottle salinities using the PRT2 temperatures 
were similar to the differences using on-scale PRT1 on nearby casts.

A few casts exhibited conductivity offsets due to biological or particulate 
artifacts.  The conductivity sensor was soaked in RBS solution prior to station 
801 to eliminate suspected organic growth on the sensor, evidenced by a 
continuing small drift in the data.  The slope and offset corrections to 
conductivity shifted at this cast because of the cleaning.  The deep drift was 
no more than .005 psu in salinity within each group, before and after the 
cleaning, and were more stable after cleaning the sensor.  Two upcasts (stas  
839  and  843) were used for pressure-series data instead of down-casts because 
of extended sections of biological contamination in the middle of the down-
casts that washed off before the up-casts.

2.8.  Bottle Sampling

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

*	CFCs
*	Helium-3
*	Oxygen
*	Total CO2
*	Alkalinity
*	AMS 14C
*	Tritium
*	Nutrients
*	Salinity
*	Barium

Note that some properties were subsampled by cast or by station, so the actual 
sequence of samples drawn was modified accordingly.

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 proper drawing order.  Normal sampling practice included 
opening the drain valve before opening 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 laboratory for analysis.  Oxygen, nutrients and salinity 
analyses were performed on computer-assisted (PC) analytical equipment 
networked to Sun SPARCStations for centralized data analysis.  The analyst for 
a specific property was responsible for insuring that their results updated 
the cruise database.

2.9.  Bottle Data Processing

The first stage of bottle data processing consisted of validating individual 
samples, and checking the sample log (the sample inventory) for consistency.  
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.  Note that the rosette bottle number was the 
primary identification for all samples taken from the bottle, as well as for 
the CTD data associated with the bottle.  All CTD trips were retained whether 
confirmed or not so that they can be available to assist in resolving bottle 
tripping problems.

Diagnostic comments from the sample log were then translated into preliminary 
WOCE quality codes, together with appropriate comments.  Each code indicating a 
potential problem would be investigated.

The second stage of processing would begin once all the samples for a cast had 
been accounted for.  All samples for bottles suspected of leaking were checked 
to see if the property was consistent with the  profile for the cast, with 
adjacent stations and where applicable, with the CTD data.  All comments from 
the analysts were examined and turned into appropriate water sample codes.  
Oxygen flask numbers were verified, as each flask is individually calibrated 
and significantly affects the calculated O2 concentration.

The third stage of processing would continue until the data set is considered 
"final".  Various property-property plots and vertical sections were examined 
for both consistency within a cast and consistency with adjacent stations.  In 
conjunction with this process the analysts would review (and sometimes revise) 
their data as additional calibration or diagnostic results became available.  
Assignment of a WHP water sample code to an anomalous sample value was 
typically achieved through consultation with one of the chief scientists.

WHP water bottle quality flags were assigned with the following additional 
interpretations:

3 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 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.

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

1 The sample for this measurement was drawn from a 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 correct, but  are open to 
  interpretation.

4 Bad measurement.  Does 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 cast.

4 Bad measurement.  The CTD data were determined to be unusable for 
  calculating a salinity.

8 The CTD salinity was derived from the CTD down cast, matched on an 
  isopycnal surface.

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

2 Acceptable measurement.

4 Bad measurement.  The CTD data were determined to be unusable for 
  calculating a dissolve oxygen concentration.

5 Not reported.  The CTD data could not be reported.

9 Not sampled.  No operational dissolved oxygen sensor was present on this cast.

Note that all CTDOXY values were derived from the down cast data, matched to 
the upcast along isopycnal surfaces.

Table 2.9.0:  Shows the number of samples drawn and the number of times each 
WHP sample quality flag was assigned for each basic hydrographic property:

Stations 708-856
			Bottle Codes			Water Sample Codes
	Reported 
	Levels	2	3	4	9	1	2	3	4	5	9
	  5117	5099	8	6	4						2
Salinity  5107					05041		52	13	1	10
Oxygen	  5107					05092		6	8	1	10
Silicate  5108					05102		2	4	0	9
Nitrate   5108					05101		1	6	0	9
Nitrite   5108					05101		1	6	0	9
Phosphate 5108					05097		5	6	0	9

Table 2.9.0 Frequency of WHP quality flag assignments.

2.10.  Salinity Analysis

Salinity samples were drawn into 200 ml Kimax high alumina borosilicate bottles 
after 3 rinses, and were sealed with custom-made plastic insert thimbles and 
Nalgene screw caps.  This assembly provides very low container dissolution and 
sample evaporation.  As loose inserts were found, they were replaced to ensure 
a continued airtight seal.  Salinity was determined after a box of samples had 
equilibrated to laboratory temperature, usually within 8-12 hours of 
collection.  The draw time and equilibration time, as well as per-sample 
analysis time and temperature were logged.

Two Guildline Autosal Model 8400A salinometers (55-654 and 57-396) located in a 
temperature-controlled laboratory were used to measure salinities.  The 
salinometers were modified by ODF and contained interfaces for computer-aided 
measurement.  A computer (PC) prompted the analyst for control functions 
(changing sample, flushing) while it made continuous measurements and logged 
results.  The salinometer cell was flushed until successive readings met 
software criteria for consistency, then two successive measurements were made 
and averaged for a final result.

The salinometer was standardized for each cast with IAPSO Standard Seawater 
(SSW) Batch P-126, using at least one fresh vial per cast.  The estimated 
accuracy of bottle salinities run at sea is usually better than 0.002 PSU 
relative to the particular Standard Seawater batch used.  PSS-78 salinity 
[UNES81] was then calculated for each sample from the measured conductivity 
ratios, and the results merged with the cruise database.

Lab temperature in lower lab (Autosal location) was very stable and consistent.  
It rarely varied from 19-21 degrees C.  As a result both autosals were setup on 
21 deg bath temp.  #57-396 had a slightly higher noise level than #55-654 so it 
was only used when #55-654 required maintenance.  #55-654 required a cell 
cleaning after station 760.  It was reinstated at sta 775.  Triplicate samples 
were drawn on sta 775, one box each was ran on each machine, one box was ran 
two weeks later on #57-396 as a test.  Autosal #55-654 was used on stations 
708-760, 775-856.  Autosal #57-396 was used on stations 761-775
2.11.  Oxygen Analysis

Samples were collected for dissolved oxygen analyses soon after the rosette 
sampler was brought on board and after CFC and helium were drawn.  Nominal 125 
ml volume-calibrated iodine flasks were rinsed twice with minimal agitation, 
then filled via a drawing tube, and allowed to overflow for at least 3 flask 
volumes.  The sample temperature was measured with a small platinum resistance 
thermometer embedded in the drawing tube.  Draw temperatures were very useful 
in detecting possible bad trips even as samples were being drawn.  Reagents 
were added to fix the oxygen before stoppering.  The flasks were shaken twice; 
immediately after drawing, and then again after 20 minutes, to assure thorough 
dispersion of the MnO(OH)2 precipitate.  The samples were analyzed within 30 
minutes to 5 hours of collection.

Dissolved oxygen analyses were performed with an SIO-designed automated oxygen 
titrator using photometric end-point detection based on the absorption of 365 
nm wavelength ultra-violet light.  Thiosulfate was dispensed by a Dosimat 665 
buret driver fitted with a 1.0 ml buret.  ODF uses a whole-bottle modified-
Winkler titration following the technique of Carpenter [Carp 65] with 
modifications by Culberson et. al [Culb 91], but with higher concentrations of 
potassium iodate standard (approximately 0.012N) and thiosulfate solution (50  
gm/l).  Standard solutions prepared from preweighed potassium iodate crystals 
were run at the beginning of each 12 hour watch, which typically included from 
1 to 3 stations.  Standards were made up every 4-5 days and compared to assure 
that the results were reproducible, and to preclude the possibility of a 
weighing error.  Reagent/distilled water blanks were determined to account for 
oxidizing or reducing materials in the reagents.  Carbon Disulfide was added to 
the thiosulfate as a preservative.  The auto-titrator generally performed very 
well.

The samples were titrated and the data logged by the PC control software.  The 
data were then used to update the cruise database on the Sun SPARCstations.

Blanks, and thiosulfate normalities corrected to 20C, calculated from each 
standardization, were plotted versus time, and were reviewed for possible 
problems.  New thiosulfate normalities were recalculated after the blanks had 
been smoothed.  These normalities were then smoothed, and the oxygen data was 
recalculated.

Oxygens were converted from milliliters per liter to micro-moles per kilogram 
using the in-situ temperature.  Ideally, for whole-bottle titrations, the 
conversion temperature should be the temperature of the water issuing from the 
bottle spigot.  The sample temperatures were measured at the time the samples 
were drawn from the bottle, but were not used in the conversion from 
milliliters per liter to micro-moles per kilogram because the software was not 
available.

Aberrant drawing temperatures provided an additional flag indicating that a 
bottle may not have tripped properly.  Measured sample temperatures from mid-
deep water samples were about 4-7C warmer than in-situ temperature.  Had the 
conversion with the measured sample temperature been made, converted oxygen 
values, would be about 0.08% higher for a 6C warming (or about 0.2M/Kg for a 
250M/Kg sample).

Oxygen flasks were calibrated gravimetrically with degassed deionized water 
(DIW) 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.  All volumetric glassware used in 
preparing standards is calibrated as well as the 10 ml Dosimat buret used to 
dispense standard Iodate solution.  Iodate standards are pre-weighed in ODF's 
chemistry laboratory to a nominal weight of 0.44xx grams and exact normality 
calculated at sea.  An experimental comparison with 0.0100N CSK Standard 
Solution Potassium Iodate (Sagami Chemical Research Center) showed good 
agreement (a  difference of <0.1%).  Potassium Iodate (KIO3) is obtained from 
Johnson Matthey Chemical Co. and is reported by the suppliers to be >99.4% pure.  
All other reagents are "reagent grade" and are tested for levels of oxidizing 
and reducing impurities prior to use.

No major problems were encountered with the analyses.  The temperature 
stability of the laboratory used for the analyses was poor, varying from 22 to 
28C over short time scales.  Portable fans were used to assist in maintaining 
some temperature stability.  The oxygen data were used to calibrate the CTD 
dissolved O2 sensor.

2.12.  Nutrient Analysis

Nutrient samples were drawn into 45 ml high density polypropylene, narrow 
mouth, screw-capped centrifuge tubes which were rinsed three times before 
filling.  Standardizations were performed at the beginning and end of each 
group of analyses (one cast, usually 36 samples) with a set of an intermediate 
concentration standard prepared for each run from secondary standards.  These 
secondary standards were in turn prepared aboard ship by dilution from dry, 
pre-weighed primary standards.  Sets of 6-7 different concentrations of 
shipboard standards were analyzed periodically to determine the deviation from 
linearity as a function of concentration for each nutrient.

Nutrient analyses (phosphate, silicate, nitrate and nitrite) were performed on 
an ODF-modified 4 channel Technicon Auto-Analyzer II, generally within one hour 
of the cast.  Occasionally some samples were refrigerated at 2 to 6C for a 
maximum of 4 hours.  The methods used are described by Gordon et al. [Atla71], 
[Hage72], [Gord92].  The colorimeter output from each of the four channels were 
digitized and logged automatically by computer (PC), then split into absorbence 
peaks.  All the runs were manually verified.

Silicate is analyzed using the technique of Armstrong et al. [Arms67].  
Ammonium molybdate is added to a seawater sample to produce silicomolybdic acid 
which is then reduced to silicomolybdous acid (a blue compound) following the  
addition of stannous chloride.  Tartaric acid is also added to impede PO4 
contamination.  The sample is passed through a 15 mm flowcell and the 
absorbence measured at 820nm.  ODF's methodology is known to be non-linear at 
high silicate  concentrations (>120  M); a correction for this non-linearity is 
applied in ODF's software.

Modifications of the Armstrong et al. [Arms67] techniques for nitrate and 
nitrite analysis are also used.  The seawater sample for nitrate analysis is 
passed through a cadmium column where the nitrate is reduced to nitrite.  
Sulfanilamide is introduced, reacting with the nitrite, then N-(1-
naphthyl)ethylenediamine dihydrochloride which couples to form a red azo dye.  
The reaction product is then passed through a 15 mm flowcell and the absorbence 
measured at 540 nm.  The same technique is employed for nitrite analysis, 
except the cadmium column is not present, and a 50 mm flow-cell is used.

Phosphate is analyzed using a modification of the Bernhardt and Wilhelms 
[Bern67] technique.  Ammonium molybdate is 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 is heated 
to 55C to enhance color development, then passed through a 50 mm flowcell and 
the absorbence measured at 820 nm.

Nutrients, reported in micromoles per kilogram, were converted from micromoles 
per liter by dividing by sample density calculated at zero pressure, in-situ 
salinity, and an assumed laboratory temperature of 25C.

Na2SiF6, the silicate primary standard, is obtained from Fluka Chemical Company 
and Fischer Scientific and is reported by the suppliers to be >98% pure.  
Primary standards for nitrate (KNO3), nitrite (NaNO2), and phosphate (KH2PO4) 
are obtained from Johnson Matthey Chemical Co. and the supplier reports 
purities of 99.999%, 97%, and 99.999%, respectively.

No major problems were encountered with the measurements.  The pump tubing was 
changed three times, and deep seawater was run as a substandard.  The 
temperature stability of the laboratory used for the analyses was poor, varying 
from 22 to 28C over short time scales.  Portable fans were used to assist in 
maintaining some temperature stability.

References:

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).

Atlas, E.L., Hager, S.W., Gordon, L.I., and Park, P.K., "A Practical Manual for 
  Use of the Technicon Auto-Analyzer(R) in Seawater Nutrient  Analyses Revised", 
  Technical Report 215, Reference 71-22, p. 49, Oregon State University, 
  Department of Oceanography (1971).

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).

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

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

Carter, D.J.T., "Computerised Version of Echosounding Correction  Tables (Third  
  Edition)", Marine Information and Advisory Service, Institute of Oceanographic 
  Sciences, Wormley, Godalming, Surrey. GU8 5UB.  U.K. (1980).

Culberson, C.H. and Williams, R.T., et al., "A comparison of methods for the 
  determination of dissolved oxygen in seawater", Report WHPO 91-2, WOCE 
  Hydrographic Programme Office (Aug 1991).

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).

Hager, S.W., Atlas, E.L., Gordon, L.D., Mantyla, A.W., and Park, P.K., "A 
  comparison at sea of manual and autoanalyzer analyses of phosphate, nitrate, 
  and silicate", Limnology and Oceanography, 17, pp. 931-937 (1972).

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).

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

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


* All figures shown in PDF file.
