CRUISE REPORT: A02 / AR07W
(Updated NOV 2018)




Highlights





                        Cruise Summary Information

               Section Designation  A02 / AR07W (MSM-28)
Expedition designation (ExpoCodes)  06M220130509
                  Chief Scientists  Dagmar Kieke / U Bremen
                             Dates  2013 MAY 09 - 2013 JUN 20
                              Ship  Maria S. Merian
                     Ports of call  St. John’s (Canada) – Tromsoe (Norway)

                                                60° 16.86' N
             Geographic Boundaries  53° 54.29' W            11° 27.14' W
                                                 47° 5.8' N

                          Stations  152
      Floats and drifters deployed  7 Argo floats deployed
    Moorings deployed or recovered  5 moorings deployed, 3 recovered

                           Contact Information:

                               Dagmar Kieke
          Tel: +49 (0)421 218-62154 • Fax: +49 (0)421 218-62165
                     Email: dkieke [at] uni-bremen.de




















                         Maria S. Merian-Berichte

NOAC
(North Atlantic Changes)


Cruise No. MSM-28


May 09 – June 20, 2013,
St. John’s (Canada) – Tromsoe (Norway)




D. Kieke, L. Abels, W. Böke, K. Bulsiewicz, C. Denker,
D. Hauck, S. Hertzberg, N. Koopmann, R. Lahl, J. Lange, J. Löb,
V. Müller, M. Peters, A. Roessler, R. Steinfeldt, I. Stendardo,
H.-H. Uhde


Editorial Assistance:
DFG-Senatskommission für Ozeanographie
MARUM – Zentrum für Marine Umweltwissenschaften der Universität Bremen
2014


 



Table of Contents


                                                                     Page
1  Summary                                                              3
2  Participants                                                         4
3  Research Program                                                     5
4  Narrative of the Cruise                                              5
5  Preliminary Results                                                  8
   5.1  CTDO Measurements and Sensor Calibration                        8
        5.1.1  CTDO Performance                                         8
        5.1.2  Oxygen Analysis                                          9
        5.1.3  CTDO Sensor Calibration                                 11
   5.2  Sampling and Analysis of Transient Tracers                     12
        5.2.1  Analysis of Sulphurhexafluoride (SF6) and 
               Chlorofluorcarbon-12 (CFC-12)                           12
        5.2.2  Offline Sampling of Chlorofluorocarbons                 14
        5.2.3  Sampling of Noble Gas Isotopes and Tritium              15
   5.3  Performance of Lowered Acoustic Doppler Current Profilers      16
   5.4  Performance of Vessel-Mounted Acoustic Doppler Current 
        Profilers                                                      17
   5.5  Recovery, Deployment, and Acoustic Telemetry of PIES           18
   5.6  Mooring Activities                                             21
        5.6.1  Mid-Atlantic Ridge Moorings                             21
        5.6.2  Deep Western Boundary Current Moorings                  24
        5.6.3  Flemish Pass Moorings                                   24
   5.7  Deployment of Profiling Floats                                 25
6  Underway Measurements                                               26
   6.1  Meteorological Data                                            26
   6.2  Thermosalinograph Data                                         27
7  Data and Sample Storage and Availability                            27
8  Acknowledgements                                                    28




1  Summary

Cruise MSM-28 was dedicated to investigating the circulation system and 
the water mass structure in the western subpolar North Atlantic. A 
special focus was on the Labrador Sea, the Newfoundland Basin and the 
West European Basin. One of the objectives of cruise MSM-28 was to obtain 
a large-scale water mass inventory regarding the anthropogenic tracers 
SF6 and  CFC-12. These will serve to estimate spreading and aging of 
Labrador Sea Water (LSW) and allow for inferring respective formation 
rates since 2011. Two mooring arrays recovered during cruise MSM-27 in 
Flemish Pass and in the region of the DWBC off Flemish Cap were intended  
to be redeployed again during cruise MSM-28. Due to severe instrument 
loss (one DWBC mooring could not be recovered during cruise MSM-27) the 
deployment of the DWBC array was entirely canceled, and the instruments 
were brought to Bremen for further inspection. As another consequence 
resulting from the instrument loss the redeployment of the Flemish Pass 
mooring array, by intention shifted from cruise MSM-27 to cruise MSM-28, 
was reduced to one out of two moorings. Canadian partners from the 
Bedford Institute of Oceanography in Dartmouth/Canada, however, deployed 
a second mooring in the Labrador Current passing through Flemish Pass in 
June 2013. So, this array presently consists of two moorings, though with 
adjusted locations. The deep-sea mooring array located at the western 
flank of the Mid-Atlantic Ridge (MAR) was successfully recovered and, 
extended by a fourth mooring, redeployed again at the MAR. Along the same 
line four inverted echo-sounders equipped with pressure sensors (PIES) 
were serviced, and four additional instruments were deployed in the 
Newfoundland Basin along 47°N. These instruments serve to estimate 
variations of baroclinic and barotropic transports of the subpolar gyre. 
Measurements carried out during cruise MSM-28 and corresponding results 
contribute to the BMBF-funded project RACE, WP 1.2, and to the DFG-funded 
project FLEPVAR.


Zusammenfassung

Die Reise MSM-28 diente der Erforschung der Zirkulation und der 
Wassermassenstruktur im westlichen subpolaren Nordatlantik. Ein 
regionaler Schwerpunkt lag auf der Labradorsee, dem Neufundlandbecken und 
dem Westeuropäischen Becken. Eines der Ziele der Reise MSM-28 bestand 
darin, ein großskaliges Wassermasseninventar in Bezug auf die 
anthropogenen Spurenstoffe SF6 und CFC-12 zu erhalten. Mit diesen lassen 
sich die Ausbreitung und Alterung von Labradorseewasser (LSW) verfolgen 
und entsprechende Bildungsraten seit 2011 ermitteln. Zwei 
Verankerungsarrays, die während der Reise MSM-27 in der Flämischen 
Passagen und im Randstromgebiet östlich der Flämischen Kappe geborgen 
wurden, sollten während MSM-28 ursprünglich wieder ausgelegt werden. 
Aufgrund von massivem Geräteverlust (eine Randstrom-Verankerung konnte 
während MSM-27 nicht geborgen werden) wurde das Randstrom-Array nicht 
wieder neu ausgelegt und die Geräte zwecks weiterer Inspektion nach 
Bremen gebracht. Als weitere, aus dem Geräteverlust resultierende 
Konsequenz, wurde das Array in der Flämischen Passage von zwei auf eine 
Verankerung reduziert. Kanadische Partner vom Bedford Institute of 
Oceanography in Dartmouth, Kanada, legten jedoch im Juni 2013 eine zweite 
Verankerung in den Labradorstrom-Bereich in der Flämischen Passage aus, 
so dass dieses Array gegenwärtig aus zwei Verankerung besteht, wenn auch 
mit angepassten Positionen. Das Tiefsee- Verankerungsarray am 
Mittelatlantischen Rücken (MAR) wurde erfolgreich geborgen und, um eine 
vierte Verankerung erweitert, wieder neu ausgebracht. Entlang derselben 
Messlinie  wurdenvier mit Drucksensoren ausgestattete Bodenecholote 
(PIES) angesprochen und vier neue Geräte im Neufundlandbecken entlang 
47°N ausgebracht. Diese Instrumente dienen der Bestimmung von barotropen 
und baroklinen Transportschwankungen des Subpolarwirbels. Die während 
MSM-28 durchgeführten Messungen und entsprechende Ergebnisse tragen zum 
BMBF-Projekt RACE, AP 1.2, bei sowie zum DFG-geförderten Projekt FLEPVAR.



2  Participants

Name                     Discipline                        Institution
———————————————————————  ————————————————————————————————  ———————————
Kieke, Dagmar, Dr.       chief scientist                           IUP
Abels, Lotte             CTDO/LADCP watch                          IUP
Böke, Wolfgang           technics, PIES/CTD/IUP moorings           IUP
Bulsiewicz, Klaus        tracer analysis                           IUP
Denker. Claudia          CTDO/LADCP watch                          BSH
Hauck, Dennis            technics, BSH moorings/float deployment   BSH
Hertzberg, Stefan        CTDO/LADCP watch                          IUP
Koopmann, Nikolaus       CTDO/LADCP watch                          IUP
Lahl, Rebecca            CTDO/LADCP watch                          IUP
Lange, Julia             tracer sampling                           IUP
Löb, Jonas               CTDO/LADCP watch                          IUP
Müller, Vasco            CTDO/LADCP watch                          IUP
Peters, Maike            tracer sampling                           IUP
Roessler, Achim, Dr.     vm-& LADCP processing, PIES analysis      IUP
Steinfeldt, Reiner, Dr.  salinometry, CTDO processing/calibration  IUP
Stendardo, Ilaria, Dr.   oxgen analysis                            IUP
Uhde, Hans-Hermann       technics, BSH moorings/float deployment   BSH

BSH  Bundesamt für Seeschifffahrt und Hydrographie, Hamburg, Germany
IUP  Universität Bremen, Institut für Umweltphysik, AG Ozeanographie, 
     Bremen, Germany



3  Research Program
  
Measurements conducted during cruise MSM-28 contribute to the cooperative 
research project RACE (Regional Atlantic Circulation and Global ChangE), 
which is funded by the German Federal Ministry of Education and Research 
(BMBF). Investigations were carried out in the framework of work package 
1.2 (NOAC, NOrth Atlantic Changes), affiliated to the University of 
Bremen, Germany, and the German Federal and Maritime Hydrographic Agency 
(BSH), Hamburg, Germany. The primary objectives of cruise MSM-28 were:

  1.  To exchange two deep-sea mooring arrays installed across the Deep 
      Western Boundary Current (DWBC) east of Flemish Cap at 47°N and 
      along the western flank of the Mid-Atlantic Ridge (MAR).  Both 
      arrays serve to measure the velocity structure and temperature and 
      salinity of different components of North Atlantic Deep Water 
      (NADW) as well as of the North Atlantic Current (NAC). Since the 
      DWBC mooring array could not be completely recovered during the 
      previous cruise MSM-27, it was not redeployed.

  2.  To analyze the strength and variability in the strength of the 
      exported NADW in relation to the variations in the strength of the 
      NAC in the Newfoundland Basin.

  3.  To infer the main pathways of the NADW components and the NAC in 
      the open subpolar North Atlantic and the strength of the subpolar 
      gyre as it crosses the MAR.

  4.  To estimate the present rate of formation of Labrador Sea Water 
      (LSW), inferred from changes of tracer inventories.

  5.  To assess the role of LSW formation and different NAC circulation 
      patterns for the lateral propagation of heat and freshwater 
      anomalies.



4  Narrative of the Cruise


Fig. 3.1.  Track chart of R/V MARIA S. MERIAN Cruise MSM-28. Numbers 
           indicate hydrographic profiles.


RV MARIA S. MERIAN left St. John's/Newfoundland on May 09th, 2013, at 
14:15 UTC. Having passed the 12 nm-zone(1), continuous logging of 
underway data (thermosalinograph and vessel-mounted Acoustic Doppler 
Current Profilers (ADCP), operated at 38 and 75 kHz) was switched on at 
16:56 UTC. Northern course was set, and station work began on May 10th, 
2013, 16:55 UTC, by conducting a first hydrographic section consisting of 
stations 271/001 to 278/008 (Table 6) that crossed the Deep Western 
Boundary Current (DWBC) at the latitude of ~53°N. Station work included 
vertical casts carried out with a conductivity-temperature-depth-oxygen 
(CTDO) sensor package and two lowered ADCPs operated at 300 kHz and 
attached to a water sampler unit. Water samples were taken with respect 
to analyze oceanic concentrations ofchlorofluorocarbon-12 (CFC-12), 
sulphurhexafluoride (SF6), salinity and oxygen. The latter two parameters 
were used to calibrate the conductivity and oxygen sensors of the CTDO 
sensor package.

Having finished this section on May 11th, RV MARIA S. MERIAN headed 
towards the northwest to begin station work along the approximate course 
of the so-called AR7W section. This hydrographic repeat line crosses the 
central Labrador Sea in northeastern direction from the Canadian to the 
Greenland continental shelf. The presence of an ice field on the Labrador 
Shelf, however, made a small detour necessary. Station work along the 
AR7W section, therefore, started at a water depth of around 3000 m and 
was carried out towards the Canadian shelf again.

Having finished the shallowest station on the Canadian side of the 
section (May 12th, station285/015, 450 m), the vessel turned towards the 
northeast and continued hydrographic station work at a water depth of 
3100 m (May 12th, station 286/016). At station distances varying between 
15 and 33 nm, RV MARIA S. MERIAN crossed the central Labrador Sea but on 
its way faced severe cross seas due to variable wind and wave conditions. 
On May 15th, the shallowest station on the Greenland side of the AR7W 
section was conducted (station 300/030). Afterwards, the vessel turned 
south and followed the 48°W meridian back into the central Labrador Sea 
again. On May 16th, the first out of seven APEX floats (Table 2) 
contributing to the global Argo program was deployed.

Having reached the southernmost station of the 48°W-section (May 17th, 
station 309/039), a southeastern course was set towards the Northwest 
Corner of the Newfoundland Basin, station distances were 32-34 nm as was 
the case for the 48°W section. On May 19th, the southernmost station of 
the section that followed the axis of the Labrador Sea was carried out 
(station 317/047). Subsequently, course was set towards north, and RV 
MARIA S. MERIAN started her ascend towards Kap Farvel at the southern tip 
of Greenland (station distances of 31 nm). Before entering the 
Greenlandic Exclusive Economic Zone (EEZ) the second APEX float was 
deployed. Very calm sea state and favorable low winds were experienced 
until May 21st. Wind rapidly increased while approaching Greenland. On 
May 22nd, wind speeds exceeded 12 Beaufort (Bf). Though station work 
could still be carried out at 10 Bf (station 334, 64), it had to be 
interrupted subsequently due to very unfavorable weather conditions.

Work was presumed again on May 23rd, when RV MARIA S. MERIAN headed 
towards the southeast and approached the Mid-Atlantic Ridge (MAR, station 
350/080). On May 24th, the third APEX float was deployed. Between May 
26th and May 29th, the deep-sea mooring GFZ (Table 4) was recovered and 
redeployed at the western exit of Charlie-Gibbs Fracture Zone, deep-sea 
moorings FFZ-1 and FFZ-2 were recovered at the western exit of Faraday 
Fracture


————————————————————————
1	nm = nautical mile


Zone, as well as four locations with inverted echo-sounders equipped with 
pressure sensors (PIES) installed at the sea-bottom were visited (Table 
3). Recorded PIES data consisting of measurements of acoustic travel time 
and pressure was retrieved via acoustic telemetry, another instrument was 
placed next to PIES BP-15 (new location BP-15a), and PIES station BP-13 
was given up by recovering the installed instrument and preparing it for 
redeployment at another location.

On May 28th, RV MARIA S. MERIAN reached the latitude of 47°N and turned 
west. While station distances were about 50 nm in the beginning, spacing 
was reduced to 2 nm when crossing the DWBC east of Flemish Cap (stations 
355/085 to 377/107). During May 31st and June 1st, four additional PIES 
were deployed along the 47°N section in the deep Newfoundland Basin. 
Furthermore, two more APEX floats were deployed on May 31st. While 
crossing the DWBC unfavorable wind and sea state conditions led to kinks 
in the conducting sea cable of the vessel's winch EL2 that was 
successfully used until then. Stations 371, 373, 375-377 were run using 
winch EL1, after which station work using winch EL2 was presumed again. 
This winch was in operation for the entire remaining time of the cruise.

Having finished hydrographic station work east of Flemish Cap, RV MARIA 
S. MERIAN left the DWBC region and sailed 136 nm towards Flemish Pass. On 
June 3rd, mooring BM-25/2 was placed on the western side of Flemish Pass 
at a water depth of ~1000 m. After another transit of 126 nm, station 
work was presumed again on June 4th at the northeastern flank of Flemish 
Cap. Another hydrographic section crossing the DWBC at station distances 
of 11 to 22 nm followed (stations 379/109 to 386/116).

RV MARIA S. MERIAN then crossed the Newfoundland Basin and headed again 
on a northeastern course towards the northern end of the PIES-line at the 
MAR (transit of 309 nm). On June 6th, hydrographic station work was 
continued along the PIES line following the western flank of the MAR 
(hydrographic stations 387/117 to 406/136). Between June 7th and June 
9th, deep-sea moorings FFZ-1 and FFZ-2 were redeployed again, and the 
entire array was extended by adding a fourth mooring (MFZ) at the western 
exit of Maxwell Fracture Zone further south.

On June 9th, RV MARIA S. MERIAN arrived again at 47°N and continued its 
course along this approximate latitude towards the eastern side of the 
subpolar North Atlantic. Station distances of 58 nm were chosen to be 
able to cross the West European Basin while measuring in the remaining 
time of the field period of cruise MSM-28. The last two APEX floats were 
deployed in the West European Basin on June 13th. On June 14th, the last 
hydrographic stations crossing the boundary current on the eastern side 
of the subpolar North Atlantic were conducted. Station distances were 
reduced to 18-38 nm. Station work was finished at 09:33 UTC the same day, 
when RV MARIA S. MERIAN started a transit of 1556 nm towards 
Tromsø/Norway, the intended port of arrival. Continuous logging of 
underway data was stopped on June 19th, 16:00 UTC. On June 20th, 04:00 
UTC, the vessel arrived at the pilot station and docked in Tromsø harbour 
at 06:40 UTC the same day, when cruise MSM-28 was finished.



5  Preliminary Results

5.1  CTDO Measurements and Sensor Calibration

5.1.1  CTDO Performance
       (R. Steinfeldt)

Profiling measurements of conductivity, temperature, pressure/depth, and 
oxygen (CTDO) were performed with a Sea-Bird Electronics (SBE) 9plus 
underwater unit with attached with sensors for temperature, conductivity, 
and dissolved oxygen. This sensor assembly was operated via a SBE-
11plusV2 deckunit. An overview of sensor types and serial numbers is 
provided in Table 5.1.


Tab. 5.1:  Summary of CTDO-related sensors used during cruise MSM-28.

parameter     sensor model  serial number  comments
————————————  ————————————  —————————————  —————————————————
pressure      SBE-9plus     60962          all profiles
temperature   SBE-3plus     03P4156        all profiles
conductivity  SBE-4C        042646         all profiles
oxygen        SBE-43        430547         profiles #1-#35
              SBE-43        430267         profiles #36-#152
pump          SBE-5         053138         all profiles


The CTDO package was lowered together with a carousel water sampler 
system of type SBE- 32 carrying 22 Niskin bottles (10 l), an altimeter, 
and two lowered ADCPs. From the Niskin bottles, water samples for ship-
board analysis of CFC-12 and SF6, offline samples for CFC-12 and CFC-11, 
tritium and helium (at 4 stations only) as well as samples for salinity 
and oxygen were drawn. The latter two served for the calibration of the 
conductivity and oxygen sensors, so the number of samples for these two 
parameters was only about three per profile.

CTDO measurements could be performed without disturbances from top to 
bottom for each profile. The only malfunction occurred at station 
#286/16, when the Niskin bottles could not be closed. Typically, the 
CTDO/water sampler system was at first deployed to a depth of about   10 
m. After the pumped had switched on the system was heaved back to the 
surface from where it was lowered towards the sea bottom. In those cases 
of harsh sea conditions, the entire system was deployed quickly to depths 
of 10 to 20 m, and after the pumped switched on, the system was 
immediately lowered to avoid formation of kinks in the conducting wire. 
In case, the pump start was below the mixed layer, the upper part of the 
profile was reconstructed from the upcast data (stations  #375/105,  
#376/106,  #400/130,  #402/132,  #403/133,  and  #405/135).  At 
station#420/150 salinity and thus density showed spurious oscillations. 
These could be reduced by setting a time delay of 0.1 s for the 
temperature sensor relative to the conductivity sensor.

The oxygen data of the CTDO system showed large oscillations up to 0.3 
ml/l especially at higher pressure (above ~1500 dbar). Therefore, after 
station #305/35 the oxygen sensor was changed (cf. Tab. 5.1). With 
increasing time of operation also the second sensor began to oscillate, 
although at a lower amplitude (up to 0.2 ml/l).

An offset of the system’s pressure sensor of -0.5 dbar was determined 
from the recorded pressure values at the beginning and end of the CTDO 
casts.


5.1.2  Oxygen Analyis
       (I. Stendardo)

In order to perform the calibration of the oxygen sensor of the CTDO 
sensor package 380 samples in total were collected during the entire 
duration of the cruise, with an average of 3 to 4 samples per station. 
However, starting from station #329 samples were not always taken at 
every station. Starting from station #341, samples were taken 
periodically every second station. The total number includes also 53 
double samples, which were measured for every second station to estimate 
the final precision of the measurements.

To measure dissolved oxygen from seawater samples standard Winkler 
titration was performed with a Metrohm 848 Titrino plus system, where the 
endpoint is determined with an electrode. The system is owned and was 
kindly made available by the oceanography group of D. Quadfasel, 
University of Hamburg. The machine was set to dynamic equivalence point 
titration mode, where the reagent was added in variable volume steps. The 
volume increments varied as a function of the slope of the curve.

The reagents used for the titration were Manganese(II)Chloride (MnCl2) 
with the concentration of 300 g dissolved in 500 ml of pure water and the 
Alkaline solution (NaOH-KI) with a concentration of 180 g of NaOH and 75g 
of KI dissolved in 500 ml of pure water. These two reagents were used 
during the sampling with the quantity of 0.5 ml each. Sulfuric acid 
(H2SO4), 500 ml dissolved in 1000 ml of pure water, was used with the 
quantity of 1 ml. Sodium thiosulfate (Na2S2O3) with the concentration of 
0.1 N (Normal) was used as stock solution, and Na2S2O3 0.01 N was used as 
a working solution by diluting the stock solution to 1:10. However, we 
also had ready-made vials of working solution of Na2S2O3 (0.01 N), which 
only needs to be made up to final volume of 1000 ml by adding pure water. 
For the standard two solutions were prepared: potassium iodate (KIO3) 
with a concentration of 0.1 N, prepared from a ready-made vial where the 
solution needed only to be made up to the exactly volume of 1000 ml; and 
potassium iodide (KI), prepared by diluting 50 g of KI in 500 ml of 
water. The standard was performed by mixing 1 ml of KIO3, 1 ml of H2SO4 
(50%) and 5 ml of KI to 100 ml of pure water and then run a normal 
titration. Usually for 1 ml of KIO3 10 ml of Na2S2O3 are needed. The 
titration was performed three times, and then a mean concentration was 
calculated. The standard was determined by dividing the amount of Na2S2O3 
usually needed to titrate 1 ml of KIO3 (10 ml) and the mean volume 
determined by the three titrations.

Originally it was intended to use the ready-made 0.01 N solution of 
Na2S2O3. These ready- made solutions are used directly for the titration, 
are quite stable, and if the titration is run within the next 2-3 days 
the calculation of the standard factor can be neglected. However, only a 
limited amount of these ready-made working solutions were left (only 3 
vials left for the entire cruise), while 9 vials of stock solutions (0.1 
N) were still available. These 9 vials were supposed to be used as a 
backup in case the vials of the working solution finished. The stock 
solution is stored for longer time and it needs an additional dilution to 
get from the 0.1 N to the 0.01 N. The stock solution is subject to 
deterioration and must be standardized with the KIO3. The amount of acid 
available for the entire cruise was calculated according to the amount of 
samples needed to calibrate the sensor and not to perform the standard 
factor. Due to the limited amount of acid, we decided to calculate the 
standard only every second day.

Oxygen sampling started on May 09th when the test station was carried 
out. Analysis of the data measured until May 13th revealed that the 
bottle samples were strikingly too low in oxygen when compared to data 
from previous years. As a consequence the stock solution was considered 
faulty. Indeed from May 09th to May 12th (stations #271/1 to #288/18) all 
working solutions were prepared from the stock solution prepared on the 
previous cruise MSM-27. The stock solution was finished and replaced with 
a new one on May 12th. Starting from May 13th, station #289/19, the 
working solution was prepared from the new stock solution. Until this day 
no standard was performed due to technical problems. The standard was 
performed starting from station #307/37 on May 17th.

From May 17th until June 06th standards were calculated every second day 
or when a new working solution was prepared from the stock solution. 
Starting on June 07th the standard analysis was performed every day. New 
stock solutions were prepared on May 21st, on June 06th, and on June 
07th, after realizing that the standard factor was too high (1.008). On 
May 21st, the MnCl2 solution was replaced with a newly prepared solution 
and was used starting from station #331/61. On May 22nd also the NaOH-KI 
solution was prepared and used starting from station #359/89.

Figure 5.1 shows the differences between the oxygen derived from the CTDO 
system and inferred from bottle samples. Due to the fact that the bottle 
measurements were observed to be too low in oxygen, an adjustment of 1% 
to 3% to the bottle oxygen was applied in order to reduce the differences 
between the CTD and bottle measurements. The error estimated by computing 
the difference between the double samples is 0.016 ml/l (0.25%) with a 
standard deviation of ±0.014 ml/l (Figure 5.2). The error estimated from 
the calculation of the standards is0.014 ml/l (0.22%). The quadratic 
error, which includes the error due to the measurements and the error due 
to the standard factor, is 0.021 ml/l (0.33%), which stands for the final 
precision of the measurements. Figure 5.2 shows the absolute differences 
between all the doubles, its mean and its standard deviation. Until the 
end of the cruise, although all reagents were changed, the standard was 
calculated and the stock solution periodically prepared, the oxygen 
measurements derived from bottle samples were found to be always too low. 
There is yet no clear reason for this offset, as it increased from the 
beginning of the cruise from 1% to 3% for the last stations.


Fig. 5.1: Left: Absolute difference [ml/l] between oxygen measured by the 
          CTDO sensor package (O2 CTD) and oxygen derived from bottle 
          samples via Winkler titration (O2 bottle) for all 152 
          hydrographic profiles. Right: bottle O2 [ml/l] versus the CTDO-
          derived O2 with linear fit (red line), R2=0.99.

Fig. 5.2: Absolute  difference  [ml/l]  of  the  particular  oxygen  
          double  samples,  displayed against profile number (cf. Chapter 
          7). Red line: mean value, red shading: standard deviation


5.1.3  CTDO Sensor Calibration
       (R. Steinfeldt)

For the calibration of the conductivity sensor, salinity samples were 
analysed with a Guildline Autosal 8400A. IAPSO standard seawater of 
batches P153 and P155 was used for the standardization of the 
salinometer. A direct comparison of the two batches did not show a 
deviation of the salinity measured by the Autosal from the salinity given 
for the batches. The CTD-derived conductivity needed a correction with a 
small additive offset of 0.0014 mS/cm.  The mean rms-error between bottle 
and CTD salinity is 0.002. Together with the uncertainty of the 
salinometer (~0.001) and the seawater batch (<0.001), the overall 
accuracy of the CTD- derived salinity is about 0.0025 (see Fig. 5.3).

The resulting temperature-salinity properties at the location of the 
inverted echo-sounder BP- 12 and at the deepest part of the eastern 47°N 
section (Fig. 5.4), where the temporal variability is expected to be very 
small, shows a good agreement with previous cruises. The maximal  
deviation is 0.002 (at 47°N, eastern basin) and 0.004 (at PIES BP-12), 
i.e. all profiles overlap within the 2-sigma error interval.

Using the oxygen values determined from the bottle samples for the 
calibration of the two CTD oxygen sensors results in an apparent temporal 
drift of the sensors. The introduction of this temporal dependence of the 
CTD oxygen in the calibration coefficients, however, leads to small 
oxygen values especially for the later profiles in comparison with 
earlier cruises from the same region. Thus, the temporal drift was 
ascribed to the titrated bottle oxygen, maybe due to degradation of the 
chemical solutions or of the measurement device. Therefore, the bottle 
oxygen was enlarged by 1 % (starting at station #275/4), 2% (from station 
#283/13 on) and 3% for station from #387/117 on, respectively, (also 
compare section 5.1.2).


Fig. 5.3: Histogram of salinity residuals displayed against number of 
          observations and split into different depth ranges (top to 
          bottom is shown in the top panel).


With this enhancement, the calibration of the CTD oxygen does not show a 
temporal dependence, only a constant offset, and corrections proportional 
to pressure, temperature and the oxygen concentration itself have been 
applied. For the second oxygen sensor, the calibration was done for the 
station #306/36 to 404/134 and #405/135 to #421/151 separately. 
Otherwise, the misfit of the calibration would be quite large (up to 0.1 
ml/l) for the last profiles. The rms error between bottle and CTD oxygen 
is between 0.05 ml/l and 0.026 ml/l for the two sensors. As for salinity, 
the oxygen within regions of low temporal variability have been compared 
with data from previous cruises. For the deepest part of the section 
along the Mid-Atlantic Ridge (stations#387/117 to #406/136, not shown) 
and the 47°N-east line (Fig. 5.5) the agreement is better than0.05 ml/l, 
justifying the multiplicative correction applied to the oxygen data 
derived from bottle measurements.


Fig. 5.4: Comparison of temperature plotted against salinity for the 
          deepest part of the West European Basin and shown for different 
          cruises, when the respective location was visited. (cruise 
          M50/4 in 2001 to cruise MSM-28 in 2013).

Fig. 5.5: Comparison of oxygen [ml/l] plotted against potential density 
          σ4 [kg/m3] for the deepest part of the West European Basin and 
          shown for different cruises, when the respective location was 
          visited. (cruise M59/2 in 2003 to cruise MSM-28 in 2013). Data 
          of cruise MSM-28 show a higher noise level.



5.2  Sampling and Analysis of Transient Tracers

5.2.1  Analysis of Sulphurhexafluoride (SF6) and Chlorofluorocarbon-12 
       (CFC-12)
       (K. Bulsiewicz)


Fig. 5.6: Location of hydrographic stations with SF6/CFC-12 sampling and 
          respective   ship-board analysis (red dots). Numbers indicate 
          profile numbers, see Chapter 7.


During cruise MSM-28 we used an analytical technique for on-board 
measurements of the trace gases sulphur hexafluoride (SF6) and the 
chlorofluorocarbon component CFC-12. The determination of the two 
compounds was performed by analysis with gas-chromatography with electron 
capture detection. Some parts of the system were changed in comparison to 
previous cruises. These changes increased the chromatographic peak 
signal, peak-shape and enhanced the limit of detection.

Water-samples were collected in 250 ml glass ampoules from 10 l Niskin 
bottles. 140 ml of this water were transferred to a water purge chamber. 
After purging of the water, the compounds were trapped in a 1/8” ID 
Porapak-Q trap. After thermal desorption the sample gases held in the 
trap were flushed onto a packed 1/8” MS5A column to remove nitrous oxide. 
The compounds were refocused then on a 1/16” Porapak-Q packed trap to 
narrow their chromatographic peaks and enhance their detection. After 
thermal desorption SF6 and CFC-12 were first separated from later 
compounds on a pre-column of type Alumina BOND/CFC (0.54 mm ID x 3m). SF6 
and CFC-12 were then separated on a main capillary column of type Alumina 
BOND/CFC (0.54 mm ID x 30m). Both tracers were then detected on a micro-
ECD.

Altogether 1693 water-samples were taken on 128 stations. Based on the 
analysis of replicate water samples, we estimated precisions of 0.7% for 
SF6 and 0.4% for CFC-12. Overall accuracy, including that of the 
calibration scale, was estimated to ~1.5% for CFC-12 and ~2.0% for SF6, 
with a limit of detection for SF6 of ~0.005 fmol/kg and ~0.001 pmol/kg 
for CFC-12. There was no analytical blank for SF6 and ~ 0.001 pmol/kg for 
CFC-12.

The analytical system was calibrated using a standard gas of known CFC-12 
and SF6 composition. The compressed gas standard was prepared in a 29-L 
Aculife-treated aluminium cylinder by Brad Hall, NOAA Earth System 
Research Laboratory. The values for CFC-12 and SF6 are based on the SIO-
98 calibration scale.

The concentrations of CFC-12 and SF6 in the deep water revealed two 
distinct maxima, which indicated the presence of recently ventilated 
water masses (Fig. 5.7). The upper maximum was located within the density 
range of Upper Labrador Sea Water (ULSW). Highest values were found 
directly in the Labrador Sea and adjacent regions. The lower maximum 
close to the bottom is attributed to the Denmark Strait Overflow Water 
(DSOW). Following the Deep Western Boundary Current from Greenland to 
47°N, the CFC-12 and SF6 concentrations in the DSOW decreased downstream. 
Whereas the penetration of DSOW is restricted to the western basin due to 
the Mid-Atlantic Ridge, the CFC-12/SF6 maximum related to ULSW was found 
throughout the whole subpolar North Atlantic. Lower tracer values in the 
ULSW are often correlated with higher salinities. This is an indication 
for the recirculation of older, more saline water within the North 
Atlantic Current and the penetration of Mediterranean Outflow Water into 
the eastern Atlantic.

In the overflow waters, some data points showed a high SF6/CFC-12 ratio. 
This excess SF6 can be interpreted as the remnant of a tracer release 
experiment in the Greenland Sea in 1996. Some of the deliberately 
released SF6 left the Nordic Seas via Denmark Strait within the DSOW and 
the Faroe Bank Channel within the Iceland Scotland Overflow Water 
(forming the North East Atlantic Deep Water, NEADW) and is still present 
in the subpolar North Atlantic.

Even the oldest deep water in the deep West European Basin along 47°N 
showed SF6 concentrations above the detection limit (minimum measured 
concentration 0.0065 fmol/kg).

The analyses of air samples gave mixing ratios of 522 ppt for CFC-12 and 
8 ppt for SF6, which is in good agreement to recently reported 
atmospheric values. Based on these atmospheric mixing ratios, the mean 
saturation of CFC-12 and SF6 in the mixed layer during the whole cruise 
was 101.5% and 102.5% respectively, i.e. there was no significant 
difference in the saturation of the two components (Fig. 5.8). 
Undersaturation mainly occurs at low surface temperatures (< 5°C). The 
highest supersaturations (>=108% for both CFC-12 and SF6) were found at 
stations#369/99 to #378/108, i.e. in a region of strong mixing of warm 
water from the North Atlantic Current and cold water from the Labrador 
Current.


Fig. 5.7: Concentrations of CFC-12 [pmol/kg] (red) and SF6 [fmol/kg] 
          (black) plotted against potential density σΘ [kg/m3]. Density 
          ranges of Upper Labrador Sea Water (ULSW), Labrador Sea Water 
          (LSW), Northeast Atlantic Deep Water (NEADW) and Denmark Strait 
          Overflow Water (DSOW) are highlighted.

Fig. 5.8: Saturation of CFC-12 (green), SF6 (black), and oxygen (blue) 
          derived from   near-surface samples and displayed against 
          temperature. A value of 1 equals a saturation of 100%.


5.2.2: Offline-Sampling of Chlorofluorocarbon Components
       (D. Kieke)


Fig. 5.9: Location of hydrographic stations with CFC-offline sampling and 
          subsequent sample storage (red dots). Numbers indicate profile 
          numbers, see Chapter 7.


For selected stations also so-called offline samples were taken from the 
Niskin bottles, with the intention to analyze the content of the 
chlorofluorocarbon components CFC-12 and CFC-11 in seawater at the home 
laboratory in Bremen. Offline sampling was considered at the beginning of 
the cruise (stations 271/1 to #278/8, Fig. 5.9), when the SF6/CFC-12 
analytical system (cf. section 5.2.1) was not yet in processing mode. 
Offline sampling was occasionally considered later on, when the SF6/CFC-
12 analytical system was either run in calibration mode or when system 
checks needed to be carried out (both cases did not allow analysis of 
samples). A small number of stations was chosen (see Chapter 7), where 
first SF6/CFC-12 samples were tapped from the Niskin bottles, which was 
followed by immediate tapping of offline samples. These offline samples 
shall serve to compare the performance of the ship-board analytical 
system with the home-based analytical system. The latter does not provide 
SF6 data but beside CFC-12 delivers information on CFC-11 concentrations. 
Between 12 and 20 offline samples were taken at the respective station 
which results in typical depth intervals between 100-400m. Double samples 
shall allow for a later verification of the precision of the CFC data.

Sample processing was done similar to the previous cruise MSM-27 with RV 
MARIA S. MERIAN. A volume of ~90 ml of seawater was collected in so-
called flow-through containers, consisting of a glass ampoule which is 
connected to a head carrying a movable central and a fixed side tubing.

By avoiding any contact to the atmosphere and thus preventing any 
contamination of the water sample the containers were detached from the 
Niskin bottles. CFC-free purified nitrogen was inserted into the glass 
ampoule to create a head space which is required to accommodate the 
thermal expansion of the included seawater sample. The glass ampoules 
were flame-sealed by closing the open end of the ampoule with a burner 
fueled with propane gas. After the flame- sealing processes was finished 
and time for cooling of the sealed glass was allowed the remaining glass 
pieces were stuck on the labeled glass ampoule. Together with the precise 
dead weight of the glass ampoule which was carefully determined earlier 
in the Bremen laboratory, knowledge of the total weight of the flame-
sealed glass ampoule is necessary for determining CFC concentrations 
later on.

The analysis of the samples at the Bremen home-lab is expected to be 
finished in 2014. Together with large-scale tracer data obtained during 
the previous cruise MSM-27 with RV MARIA S. MERIAN, these data will be 
used to calculate tracer inventories for the different types of LSW and 
to infer the respective rate of formation since 2011.


5.2.3  Sampling of Noble Gas Isotopes and Tritium
       (D. Kieke)

During cruise MSM-28 a very limited number of water samples were taken 
with respect to measuring helium isotopes (3He, 4He), neon, and the 
radio-active hydrogen isotope tritium at the Bremen laboratory for helium 
isotopes analysis helis (www.noblegas.uni-bremen.de). The overall 
intention was to study the correlation of tritium and its decay product 
3He with CFCs in the central Labrador Sea in relation to the stations 
located close to the Greenland coast. Altogether 48 samples for 
helium/neon isotope analysis and 48 samples for tritium analysis were 
taken at three stations close to the Greenland shore (#314/44, #328/58, 
#334/64) and one station in the central Labrador Sea (#291/21), see 
Chapter 7.

Helium isotopes and neon will be analyzed from the same water sample, 
with each water sample being stored in a gas-tight copper tube. Water 
samples for tritium analysis were stored in 1 L glass bottles that were 
water-vapour tight. Consequently, tritium as HTO molecules in oceanic 
water samples will be indirectly detected through measurement of the 
tritium decay product 3He. For this reason, the sample will be injected 
into an extraction unit that removes all dissolved gases and reduces the 
helium content of the water sample by a factor of 106. For several months 
the increase of 3He resulting from the radioactive decay of tritium is 
accumulated in the sample, and the 3He and 4He content will be measured 
subsequently using a sector-field mass spectrometer. Measuring 4He is 
required here to identify potential contamination from atmospheric air. 
In contrast, helium isotopes and neon contained in water samples stored 
in copper tubes will be detected by firstly, stripping of all dissolved 
gases from the water and transferring them into glass ampoules. Under 
vacuum conditions the resulting gas samples are transferred into a multi-
step cryogenic system that removes all gases except helium and neon. The 
sample will be injected into quadrupol mass spectrometer for 4He and 20Ne 
analysis and subsequently into a sector-field mass spectrometer for 3He 
and 4He. The mass-spectrometric sample analysis is expected to be 
finished in fall 2014.


5.3  Performance of Lowered Acoustic Doppler Current Profilers
     (A. Roessler)

The lowered acoustic Doppler current profiler (LADCP) setup in use 
consisted of two Teledyne RD Instruments (TRDI) Workhorse Monitor ADCPs, 
operating at 300 kHz and attached to the carousel water sampler. The 
instruments were configured to operate in a synchronized master (s/n 
7915) and slave (s/n 1973) configuration, where the downward looking 
master triggers the upward looking slave. The configuration was the same 
as on preceding cruise MSM-27 with RV MARIA S. MERIAN. The instruments 
were powered by an external battery supply, which consisted of 35 
commercial quality 1.5 V batteries lasting around 38 h to 40 h. These 
were assembled in a modified Aanderaa pressure housing. The system was 
configured to a ping rate of 1 Hz and 10 m depth cell size (bin length). 
Due to configuration of the carousel water sampler with additional 
weights installed, the instruments were very stable in the water column. 
Throughout all stations the devices had a mean tilt of -0.5° with a 
standard deviation of 1.2°. It only increased due to strong currents or 
especially due to the rolling of the ship, but never reached the maximum 
tolerable angles. LADCP data were recorded on all CTDO casts. In total 
152 CTDO/LADCP casts were made. Profile 102 only consists of a downcast 
profile due to a battery failure and the profiles 59 and 111 have to be 
analysed in more detail due to weird compass information, partly corrupt 
files. At some occasions the communication with the instruments via the 
battery case connection did not function properly, but a proper cleaning 
of all plug connections did help most of it. On one of such events, the 
communication cable between the computer and the battery case was found 
broken. The break occurred just next to the underwater plug due to a high 
stress exerted on the material when plugging and end-plugging the 
connections before and after each station. After replacing the cable no 
further problems arose.

Data processing was done using the LADCP-toolbox for MATLAB, version 
1.2.1, of the University of Bremen. An inverse method incorporating the 
bottom track velocities was used for most of the post-processing of the 
raw data. For the those profiles, when applying the inverse method 
resulted in a large number of spikes or unreliable velocity estimates, 
the mean of the down- and up-cast shear solution was used. The main 
reason for the spiky and/or noisy inverse solutions were the ship 
movements which led to vertical instrument velocities oscillating usually 
by ±0.5 m/s around the nominal heave and veering velocities (Fig. 5.10). 
During storm events or rougher sea states the rolling of the ship led 
even to velocities of up to +0.7 m/s although the CTDO system was lowered 
with -1 m/s. This resulted in vertical movements of the carousel water 
sampler carrying the sensor package of up to 6 m.

Beside this ship movement, which induced most of the spikes and noise in 
the inverse solution, the overall performance of the two instruments was 
very good (Fig 5.11). The range of each instrument was typically 150 m in 
the upper parts of the water column and about 50 m at depths exceeding 
2000 m. Thus, the total range of both instruments varied from 150 to 300 
m. With lowering and heaving velocities of 1 m/s - 1.2 m/s, this range 
corresponds to around 200 estimates of current shear in each depth cell 
in the deep water, and much more towards the sea surface, depending on 
the abundance of scatterers.


Fig. 5.10: Vertical velocity [m/s] of the LADCP/CTDO instrument package 
           recorded during calm (top), typical (middle), and stormy, i.e. 
           wavy, conditions (bottom).

Fig. 5.11: Percent good of the received data (red) and the corresponding 
           standard deviation (blue) over all four beams from all 
           profiles over all depth levels. The green broken line depicts 
           the 30% level which was used as the lower threshold.


5.4  Performance of Vessel-Mounted Acoustic Doppler Current Profilers
     (A. Roessler)

Two vessel-mounted acoustic Doppler current profilers (VMADCP) from 
Teledyne RD Instruments (TRDI) were used simultaneously for continuous 
recording of single-ping velocity data in the upper water column: a 75 
kHz Ocean Surveyor (OS) and a 38 kHz OS, both with flat phased-array 
transducers. The 75 kHz OS was mounted into the hull of the ship, and the 
38 kHz instrument was installed in the sea chest of the ship.

Since the VMADCPs do not have any further inbuilt sensors, all additional 
data on heading and tilt as well as the GPS position were obtained from 
the ship's Seapath system. Recording  was carried out with the TRDI VmDas 
software. The measurements were started on May 09th at 17:17 UTC, while 
the recording of usable data started on May 10th at 11:53 UTC due to some 
problems with the software settings. Recording stopped on June 19th at 
16:00 UTC. All systems operated flawless throughout the cruise, except 
for three interruptions of one of the three GPS transmission channels. 
The interruptions occurred when the recording was stopped and restarted 
to produce a new set of data files. Due to the redundancy of the 
information these interruptions only resulted in a failure of the 
standard data conversion and water-track calibration routines in MATLAB, 
while the data can be opened and analysed with the TRDI WinADCP software 
without problems. A more thorough investigation is needed to solve this 
MATLAB coding problem. The corresponding gaps are visible in Figure XX, 
one on the section between the 48°W/44°W-sections and the second just 
west of the Mid-Atlantic Ridge on 47°N.

Data of the 38 kHz OS were collected in 32 m bins in narrowband mode to 
achieve maximum range around 1400 m. The 75 kHz OS was set to a bin 
length of 16 m in narrowband mode, which resulted in a range around 700 
m. Depending on the ship motion and wave activity the maximum ranges were 
often reduced. This occurred especially during station work, when the 
instruments were disturbed to a varying degree by the ship's pump jet, 
which prevented meaningful records or increased the noise level of the 
measurements, if its outflow of the pump jet hit the instruments 
transducers. The strongest decrease was found in the 38 kHz OS data 
during stations with lots of ship movement (up to half of the maximum 
range) or during the  storm experienced near Cape Farewell (temporal 
complete loss of signal).

During post processing of the VMADCP data a water-track calibration was 
performed to determine phase and amplitude of the transducer 
misalignment. An amplitude factor of 0.998 and a misalignment angle of -
0.89° were obtained for the 38 kHz OS. For the 75 kHz device the 
amplitude factor and misalignment angle were determined as 0.99 and -
3.31°, respectively.  These values are nearly the same as in the previous 
cruise MSM-27 with RV MARIA S. MERIAN.

Data processing was done using the VMADCP-toolbox OSSI for MATLAB, 
version 14, of the Geomar Helmholtz Centre for Ocean Research Kiel. 
Figure 5.12 shows the velocity structure of the upper ocean (50-100 m), 
where especially the boundary currents of the Labrador Sea as well as the 
North Atlantic Current off Flemish Cap, in the Northwest Corner and west 
of the Mid- Atlantic Ridge stand out.


Fig. 5.12: Mean current velocity and direction averaged over 10 minutes 
           and derived from the merged VMADCP data in the top 50 to 100 m 
           of the water column (plotted once every hour for better 
           visualisation).



5.5  Recovery, Deployment, and Acoustic Telemetry of PIES
     (A. Roessler)


Fig. 5.13: Inverted echo-sounder equipped with pressure sensor (PIES, s/n 
           303) which is fixed on a tripod that serves as a bottom 
           weight. Attached are a flag and a pick-up line that will 
           facilitate retrieval and recovery at the end of its mission. 
           Photo by A. Roessler.

Fig. 5.14: Map showing the location of inverted echo-sounders equipped 
           with pressure sensors (PIES) that were serviced and/or 
           installed during cruise MSM-28.


Starting in 2006 an array of four inverted echo-sounders equipped with 
pressure sensors (PIES, Fig. 5.13) was deployed to the west of Mid-
Atlantic Ridge (MAR) to estimate the transport variability of the North 
Atlantic Current (NAC) as it crosses from the western to the eastern 
basin (BP-12 to BP-15, Figure 5.14). Another previously existing 
extension along the western part of the 47°N section was re-rigged with 
new devices at four new locations (BP-27 to BP-30, Fig. 5.14) with the 
intention to investigate the transport variations of the NAC in the 
interior of the basin, mainly the re-circulation.

PIES are deployed free-falling and are mounted on a tripod to stand on 
the sea floor (Fig. 5.13). They measure the acoustic round trip travel 
time between the acoustic transducer and the sea surface by sending a 
ping at a frequency of 12 kHz. Every 30 minutes 12 pings are sent, 
alternating 16 s and 18 s to avoid aliasing by surface waves. The high 
precision bottom pressure sensor allows the detection of relative bottom 
pressure variations caused by the water column as it moves across the 
PIES. The devices are planned to stay on-site for a period of three years 
and have been configured to allow transmission of recorded data via 
acoustic telemetry. Acoustically transmitted data consist of daily 
averages. By recovering the entire instrument and directly reading out 
the data, the full resolution time series can be retrieved.

Table 5.2 summarises the PIES-related activities carried out during 
cruise MSM-28. These activities include recovery of one instrument, 
deployment of five of them, including the recovered PIES and reading out 
the data of the four installed devices via acoustic telemetry.


Tab. 5.2: List of PIES activities carried out during cruise MSM-28. PIES: 
          Inverted echo-sounder with pressure sensor. All instruments 
          were equipped with flags, radio senders and flashers. All times 
          are given as UTC.

 PIES     s/n  Latitude    Longitude   Depth  Deployment  Telemetry    Recovery     CTD
  ID                                    [m]   Date/Time   Date/Time    Date/Time    Profile
————————  ———  ——————————  ——————————  —————  ——————————  ———————————  ———————————  ———————
BP-12/4   201  47°40.11'N  31°08.95'W  4090      ---      29 May 2013     ---       355/085
                                                          10:57-13:30               406/136
BP-13/3   272  49°01.15'N  32°36.69'W  3952      ---      28 May 2013  28 May 2013  354/084
                                                          17:26-22:06  22:27-23:48
BP-14/2   271  51°25.70'N  35°26.33'W  3604      ---      27 May 2013     ---       351/081
                                                          04:41-07:54               391/121
BP-15/2   075  52°30.50'N  36°51.60'W  3386      ---      26 May 2013     ---       439/079
                                                          03:00-05:38               387/117
BP-15a/1  235  52°30.48'N  36°51.63'W  3386   26 May 2013     ---         ---       349/079
                                              05:51-06:59
BP-27/1   272  47°05.84'N  40°52.53'W  4498   01 Jun 2013     ---         ---       366/096
                                              11:23-13:15
BP-28/1   240  47°09.68'N  39°30.06'W  4584   31 May 2013     ---         ---       364/094
                                              22:26-00:25
BP-29/1   302  47°12.52'N  38°31.09'W  4610   31 May 2013     ---         ---       362/092
                                              11:39-13:33
BP-30/1   303  47°17.52'N  36°21.47'W  4546   31 May 2013     ---         ---       360/090
                                              00:25-01:58


The first telemetric data transmission started on May 26th with the 
retrieval of the data of PIES BP15-2 from the last year. The ship’s 
hydrophone on the pneumatic extension worked very well, and nearly no 
interferences were recorded, so it was not necessary to use our own 
hydrophone which is otherwise hung over the side of the ship and lowered 
up to 20 m under the ship’s hull. All further telemetric data recordings 
and communication with the devices were done using the ship’s hydrophone. 
Due to noise and bubbles inflicted by the use of the pump jet to keep the 
ship on position, this year it was just possible at one station (BP-14/2) 
to read out the data via telemetry while doing at the same time a CTD 
cast.

After the successful data transmission a second PIES was deployed at the 
same position (BP-15a/1). The idea of having two devices at this position 
was based on the knowledge that towards the northern end of the MAR-PIES-
array the importance of the barotropic transports increases. This, 
however, can only be measured by from the pressure variations recorded by 
the bottom pressure sensor of the PIES. The respective signal is hardly 
gained via alternative methods. This is in contrast to the baroclinic 
transports, which are derived from the measured round trip travel times, 
where eventual data gaps can be reconstructed from satellite altimetry 
data. Installing two devices with a temporally and spatially overlapping 
deployment scheme will secure the availability of pressure records at the 
northern end of the array.

After the deployment it was not possible to measure the exact bottom 
position of PIES BP-15a/1, because the device did not respond properly to 
the ranging command. On the other hand, it started the expected half-
hourly measurements and transmitted successfully the first measured 
values via burst-telemetry.

On May 27th the data of the last year was recovered from BP-14/2. This 
station was the only one where it was possible to start the telemetry 
session during the CTD cast. The data was transmitted, although the 
connection was not the best and the gain of the deck unit had to be set 
8/9. After the end of the CTD cast and when the pump jet was turned off, 
the gain could be reduced to 6. The pump jet evoked a strong damping of 
the transmitted signals at this station.

After the successful telemetric data transmission of PIES BP-13/3 (May 
28th), the respective device was recovered since it was intended to be 
placed at a new location. Data retrieval was done before recovering via. 
After the release command was sent, the ascend of the PIES was closely 
followed by recording ping signals every 4 s. Based on the “ascending-y”, 
which consists of the direct ping and the reflected ping on the sea 
floor, the distance above the sea floor can be determined (Fig. 5.15). 
After spotting the device at the sea surface, it was recovered within 15 
minutes by the ship’s crew.


Fig. 5.15: Output of the PIES data processing software showing the 
           expected “Y” that indicates the ascend of PIES BP-13/3 towards 
           the sea surface after having received the ‘release’ command 
           and having detached itself from the bottom weight. Green dots 
           indicate 12 kHz acoustic signals.


The last telemetric data transmission session took place on May 29th with 
the intention to retrieve data recorded by the PIES BP-12/4. The 
telemetry was also started after the end of the CTD cast, but was twice 
disturbed from the noise of pilot whales, which were passing by the ship. 
The disturbances were short enough, so that the telemetry session had not 
to be halted. After all these successful telemetry sessions, we turned 
west to continue our cruise towards Flemish Cap along 47°N to deploy the 
four remaining devices.

The four PIES locations in the Newfoundland Basin were chosen based on 
the mean transport computed from LADCP measurements of three previous 
cruises, to best resolve the recirculation of the NAC at 47°N. The PIES 
at position BP-30/1 was the first one, which was deployed shortly after 
midnight on May 31st, while the next two devices (BP-29/1 and BP-28/1) 
followed around noon and late evening the same day. The last PIES (BP-
27/1) was deployed on June 1st. The exact bottom position could only be 
determined of the latter three, since BP-30/1 showed the same behavior as 
the newly deployed BP-15a/1 discussed above. The exact position of the 
instruments on the sea floor has to be determined via trilateration. For 
this reason, the distance between the PIES and the vessel slowly moving 
along a hook-like track with the presumable PIES location in the center 
of the hook, was measured using the ranging mode of the PIES.  This 
information was further on used to determine the point of intersection. 
The three instruments drifted 889 m, 384 m and 680 m during their 
deployment, respectively.



5.6  Mooring Activities

Mooring activity during MSM-28 consisted of recovering and redeploying an 
array of deep-sea moorings to the west of the Mid-Atlantic Ridge (MAR, 
BMBF-funded project RACE) and installing a current meter mooring in 
Flemish Pass (DFG-funded project FLEPVAR).


5.6.1  Mid-Atlantic Ridge Moorings
       (C. Denker)


Tab. 5.3: Moorings deployed/recovered at the Mid-Atlantic Ridge. All 
          times are given as UTC. All recovered moorings were equipped 
          with Iridium beacons and flags. GFZ/2 was also deployed with an 
          attached Iridium beacon.

Mooring   Latitude   Longitude   Depth  Deployment     Recovery       CTD 
  ID                              [m]   Date/Time      Date/Time      Profile
———————  ——————————  ——————————  —————  —————————————  —————————————  ———————
GFZ/1    52°35.00'N  36°56.00'W   3269      ---         26 May 2013    350/080
                                                        09:20 – 12:52
GFZ/2    52°35.00'N  36°56.00'W   3269   26 May 2013         ---       350/080
                                         16:09 – 19:35
FFZ-1/4  50°58.35'N  34°51.00'W   4327      ---         27 May 2013    352/082
                                                        11:15 – 15:03
FFZ-1/5  50°58.35'N  34°51.00'W   4335   07 Jun 2013         ---       393/123
                                         06:57 – 11:37
FFZ-2/4  49°55.66'N  33°49.66'W   4194      ---         28 May 2013    353/083
                                                        06:45 – 10:45
FFZ-2/5  49°55.01'N  33°49.90'W   4030   08 Jun 2013         ---       398/128
                                         07:02 – 11:03
MFZ/1    47°59.99'N  31°24.99'W   4020   09 Jun 2013         ---       405/135
                                         07:02 – 11:03


Fig. 5.16: Array-design of deep-sea moorings installed at the Mid-
           Atlantic Ridge in 2012/2013 and recovered during cruise MSM-28 
           (top) and moorings deployed along the same line in summer 2013 
           (bottom).


5.6.1.1  Instrumentation

All recovered moorings were equipped with an Iridium beacon attached to 
the top buoy. These beacons use an Iridium Short Burst Data (SBD) mode 
for transmitting positional information at defined intervals. Below the 
surface the beacon sits in a stand-by (underwater) mode for energy 
efficiency. There was one Iridium beacon at each mooring (GFZ/1, FFZ1/4, 
and FFZ-2/4). The beacons at GFZ/1 and FFZ-1/4 did not send any 
information due to an empty battery. The beacon at FFZ-2/4 was still in 
the underwater mode during the recovery but while on deck the beacon sent 
the positional information after waking up from its underwater mode. One 
beacon got a new battery pack and was attached to the new mooring 
(GFZ/2). The housing of the other two beacons was damaged and was later 
on sent in for repair.

Each mooring is equipped with 18 – 21 instruments to measure the 
temperature, conductivity, pressure, current velocity, and direction 
along the water column. The instruments are attached to the wire between 
300m and 3100m depth.

The NKE thermistors have temperature and pressure sensors that measure in 
a five minute sampling interval. The temperature precision is ±0.05°C in 
a 0°C/20°C range with a maximum resolution of 0.01°C. The ceramic 
membrane pressure sensor has a precision of 12m (0.3%) and a resolution 
of 1.2m.

AADI Aanderaa Recording Current Meters (RCM 7/8/9 and Seaguards) measure 
speed, direction, temperature, and pressure (optional) in a 60 minutes 
sampling interval. The accuracy of the temperature sensor is ±0.05°C, of 
the optional pressure sensor ±0.5% of the full range, the resolution of 
the compass is 0.35° and its accuracy ±5°, and the precision of the speed 
sensor is±1 cm/s.

SBE (Sea-Bird Electronics) 37-SM MicroCATs were programmed to measure the 
temperature, conductivity, and pressure (optional) in a five minute 
sampling interval. Their accuracies are 0.0003 S/m for the conductivity 
sensor, 0.002°C for the temperature sensor, and 0.1% of full scale range 
for the optional pressure sensor.

SBE 16plus V2 SEACATs measure the same parameters as MicroCATs but due to 
their high battery consumption and smaller memory space they were 
programmed to measure in a 30 minute sampling interval. The conductivity 
sensor of a SEACAT has an accuracy of 0.0005 S/m, the temperature sensor 
0.005°C, and the optional pressure sensor 0.1% of full scale range.


5.6.1.2  Calibration

Before their deployment the 10 SEACATs were strapped onto the water 
sampler unit carrying a CTD sensor package for calibration (station 306, 
profile #36; station 311, #41). The water sampler was stopped at 
3000dbar, 2000dbar, 1000dbar, and 500dbar for 10 minutes at each depth. 
Instruments were programmed to measure in a 15 seconds interval. The mean 
temperature offset was around ±1.3e-3°C. The conductivity sensor had an 
offset of about ±1.32e-1 S/m. The one SEACAT with a pressure sensor had 
an offset of ±1.25 dbar.

The recovered 14 MicroCATs and 17 NKE thermistors have also been strapped 
onto a CTD water sampler unit for calibration (station 384, profile # 
114). The sampling interval was set to10 seconds. The CTD was stopped 
four times (3500dbar, 3000dbar, 2000dbar, and 1000dbar) for 10 minutes.

The mean calculated offsets for the MicroCATs are about ±4.5e-4°C for the 
temperature sensor, around ±2.7dbar for the pressure sensor, and about 
±4.1e-4 S/m for the conductivity sensor.

The mean calculated offset for the NKE thermistors is around ±7.7e-3°C 
for the temperature sensor. One of the NKE thermistors (s/n 32018) had a 
malfunction and wasn’t included in the calculation of the mean offset.


5.6.1.3  Recovery and redeployment


The first mooring to be recovered was the northern GFZ mooring on May 
26th. The release code was sent at 09:35 UTC. The IXSEA OCEANO deck unit 
did not detect a response from the release devices. Next to the IXSEA 
deck unit the Benthos DS7000 deck unit connected to the ship’s hydrophone 
was used to listen for any responds of the acoustic release. The Benthos 
deck unit was able to detect the ping signals and was able to follow 
their way up towards the surface.

Ten minutes after the first release code was sent the top buoy was seen 
at the surface. The Iridium beacon did not send any information about its 
position. At 12:45 UTC the mooring was recovered completely. All 18 
instruments (seven current meters, five MicroCATs, and six NKE 
thermistors) worked properly.

At 19:53 UTC the GFZ mooring had been redeployed at 3270m depth equipped 
with seven current meters, three SEACATs, and ten NKE thermistors.

On May 27th at 11:25 UTC the release code for mooring FFZ-1 was sent. 
After five minutes the top buoy was seen at the surface and at 15:03 UTC 
the mooring was back on deck. The mooring included 18 instruments (seven 
current meters, four MicroCATs, six NKE thermistors, and one thermistor 
chain). During the recovery one of the NKE thermistors (s/n 32013) was 
loose and couldn’t be recovered. Two current meters (RCM9: s/n 309 and 
RCM7: s/n 11995) had a water leak which destroyed all data. Due to 
battery loss another current meter (Seaguards/n 243) stopped recording on 
March 9th, 2013.

Mooring FFZ-1 was redeployed on June 7th at 11:37 UTC (top buoy drawn 
under surface) with 21 instruments (seven current meters, four SEA-/ 
MicroCATs, and ten NKE thermistors) which will record data for the next 
12 month.

The recovery of mooring FFZ-2 took place at May 28th. 10 minutes after 
the release code was sent (06:44 UTC), the top buoy was discovered at the 
surface. The beacon at the top buoy had not sent any signals until it was 
back on deck. At 10:45 UTC the mooring was completely recovered. The 
mooring FFZ-2 was equipped with 19 instruments (seven current meters, 
five MicroCATs, six NKE thermistors, and one thermistor chain).

One current meter (Seaguard s/n 104) did not record any data due to an 
empty battery. The other Seaguard (s/n 242) stopped recording on March 
9th, 2013 due to a battery failure. The thermistor chain got a water leak 
which damaged all data.

The redeployment of mooring FFZ-2 was on June 8th. The top buoy left the 
surface at 11:03. The mooring contains 21 instruments (seven current 
meters, five SEA-/ MicroCATs, and nine NKE thermistors).

A fourth mooring (MFZ) was placed at the western entrance of the Maxwell 
Fracture Zone. It was deployed on June 9th at 21:32 UTC, equipped with 20 
instruments (seven current meters,five SEA-/ MicroCATs, and eight NKE 
thermistors).

The GFZ is the only mooring which is equipped with an Iridium beacon for 
the upcoming period. Due to mentioned failures and some connection 
problems the other Iridium beacons will be sent in for repair.


5.6.2  Deep Western Boundary Current Moorings
       (D. Kieke)

Originally, it was intended to re-install the array of deep-sea moorings 
in the Deep Western Boundary Current (DWBC) east of Flemish Cap. These 
moorings were recovered during the previous cruise MSM-27 with RV Maria 
s. Merian. However, one out of three moorings could not be recovered 
during cruise MSM-27 and consequently was considered lost. Instruments 
and material of the two recovered moorings showed considerable traces of 
material corrosion. For this reason the redeployment of the DWBC-array 
was canceled, but instead the entire mooring equipment was sent to Bremen 
for detailed inspection and instrument refurbishment.


5.6.3  Flemish Pass Moorings
       (D. Kieke)


Tab. 5.4  Overview of Flemish Pass mooring activities conducted during 
          cruise MSM-28. All times are given as UTC. The mooring was 
          equipped with two radio beacons, two flashers, and a flag.

Mooring  Latitude    Longitude   Depth  Deployment       CTD 
   ID                             [m]   Date/Time      Profile
———————  ——————————  ——————————  —————  —————————————  ———————
BM-25/2  47°07.11'N  47°06.38'W  1014   03 Jun 2013    378/108
                                        16:54 – 17:10 


As part of the DFG-funded project FLEPVAR, one mooring (BM-25/2) was 
deployed on the western side of Flemish Pass on June 03rd. Originally, it 
was intended to install another mooring in the center of Flemish Pass and 
occupy the location of the mooring BM-26/1, previously recovered during 
cruise MSM-27, once again. Due the loss of instruments installed in the 
DWBC, any acoustic release device could no longer be provided. Therefore, 
just one mooring, consisting of an Acoustic Doppler Current Profiler 
(ADCP) of type Longranger, an SBE- MicroCAT, buoyancy, and one acoustic 
release was installed. After consulting Canadian cooperation partners, 
the group around B. Greenan (Bedford Institute of Oceanography, 
Dartmouth, Canada), deployed a second current meter mooring at 47°N in 
the Labrador Current passing through Flemish Pass. Deployment was carried 
out in June 2013 during a Canadian research cruise with RV HUDSON, so, 
presently, the Flemish Pass array consists of two moorings again.


5.7  Deployment of Profiling Floats
     (C. Denker)

All floats were equipped with SBE sensors for pressure, temperature, and 
conductivity. The respective floats were programmed to drift for 10 days 
at a fixed pressure of 1500 dbar. From this parking depth the floats will 
descend down to a profiling pressure of 2000 dbar before rising and 
collecting profiles of pressure, temperature, and conductivity on their 
way to the surface. At the surface they will transmit the collected data 
via satellite. After finishing their transmission the floats will descend 
to its parking depth, and the profile cycle starts all over again. The 
floats have a typical life time of around four years. All data is usually 
available within hours after collection from the Argo data centers. Table 
5.5 lists all APEX floats, Figure 5.17 shows the deployment positions.


Fig. 5.17: Map showing the location of deployed Argo-floats. Numbers 
           indicate WMO-numbers.


Tab. 5.5: Argo-floats deployed during cruise MSM-28. All times are given 
          as UTC.

Float  WMO-ID   Argos    Latitude   Longitude   Deployment    CTD-
 s/n             -ID                            Date/Time    Profile
—————  ———————  ——————  ——————————  ——————————  ———————————  ———————
6655   4901417  128461  56°36.65'N  48°00.75'W  16 May 2013  307/037
                                                   23:14
6656   4901418  124862  56°22.39'N  43°56.16'W  20 May 2013  326/056
                                                   23:26
6657   4901419  128463  56°29.51'N  40°57.48'W  24 May 2013  339/069
                                                   05:24
6658   4901420  128464  47°11.18'N  39°00.49'W  31 May 2013  363/093
                                                   18:03
6659   6901227  128465  47°17.57'N  37°21.38'W  31 May 2013  360/090
                                                   02:22
6660   6901228  128466  48°42.67'N  17°05.72'W  13 Jun 2013  416/146
                                                   03:22
6661   6901229  128467  48°57.45'N  14°13.33'W  13 Jun 2013  418/148
                                                   18:45


Float-related activities conducted during cruise MSM-28 consisted of 
seven profiling floats of type APEX deployed on behalf of the BSH. They 
were deployed along the cruise track with a regional focus on the western 
and eastern subpolar North Atlantic. The float deployments contribute to 
the international Argo program. Argo is a global array of free-drifting 
profiling floats.



6  Underway Measurements
   (D. Kieke)

Underway measurements carried out during cruise MSM-28 by RV MARIA S. 
MERIAN were logged in time steps of 1 second by the vessel’s Davis-Ship 
system (DSHIP). Acquired data of interest included navigational 
information, near surface hydrography (temperature, conductivity, and 
thus salinity) measured by the vessel's thermosalinograph (TSG) or the 
automatic weather station operated by the German Weather Service (DWD) 
(water temperature only), water sounding data recorded by the echo-
sounder system as well as further meteorological parameters recorded by 
the weather station. All underway data relevant to this cruise were 
exported from the database on a daily basis and converted into MATLAB-
readable netCDF-files.


6.1  Meteorological Data

Meteorological parameters were recorded by the automatic weather station 
aboard RV MARIAS. MERIAN, operated by the DWD. Noteworthy meteorological 
conditions were snowfall in the western Labrador Sea (May 11th/12th) and 
several storm situations with peak absolute wind speeds exceeding 20 m/s 
(9-12 Beaufort) on May 22nd, June 02nd, June 12th, and June 14th. 
Meteorological conditions and sea surface state particularly hampered 
station work to the south of Kap Farvel at the southern tip of Greenland 
(May 22nd/23rd). Consequently, station work had to be interrupted by one 
day and the section crossing the Irminger Sea in southeast direction was 
not started until reaching the 3000m isobaths (Fig. 3.1, Chapter 7). 
Shallower casts, therefore, could not be carried out. High wind and sea 
state conditions also affected hydrographic station work when crossing 
the DWBC east of Flemish Cap (June 02nd) as well as crossing the West 
European Basin (June 12th and 14th). Atmospheric pressure was in general 
variable and ranged from about 1000 hPa to 1030 hPa. Atmospheric 
temperatures ranged from -2°C (recorded during snow fall in the western 
Labrador Sea) to up to +16°C. Figure 6.1 presents time series of the 
major meteorological parameters recorded by the automatic weather 
station.


6.2  Thermosalinograph Data

Thermosalinograph (TSG) data were recorded by respective sensors 
integrated into the vessel’s clean seawater system installed in the 
vessel’s echosounder room. Two water suction points exist at a water 
depth of about 6.2 to 6.8m. The flow rate measurement system consists of 
two seawater measurement containers, with one being active at a time and 
the second one being on stand-by. Use of containers typically switches 
after 12 hours. Throughout the cruise, twice a day seawater samples were 
drawn by the ship’s staff from the two different seawater containers. 
These samples were measured onboard using a salinometer of type Guildline 
Autosal, model 8400A. At the end of the cruise respective salinometer and 
TSG data was sent by the ship’s officers to the IfM-ZMAW in Hamburg, 
where the quality of the TSG data of RV MARIA S. MERIAN is checked on a 
routine basis. Figure 6.2 shows a first and preliminary comparison of raw 
TSG data and calibrated CTD values recorded at 6 dbar, which matches 
about the depth of the water inlet point.


Figure 6.1: Meteorological conditions observed during May 09th to June 
            20th, 2013, cruise MSM-28. Gray thin lines denote the 
            beginning of CTD station activities, blue horizontal lines 
            and scale on the right side of the figure indicate absolute 
            wind speeds reported on the Beaufort scale.

Figure 6.2: Comparison of raw TSG data (red lines) recorded during cruise 
            MSM-28 by RV MARIA S. MERIAN and calibrated CTD values 
            recorded at 6 dbar (black dots). Gray thin lines denote the 
            beginning of CTD station activities. High 
            salinity/temperature events e.g. recorded on May 31st and 
            June 01st denote those situations when the warm and saline 
            North Atlantic Current was crossed, low salinity/temperature 
            events indicate the crossing of the fresh and cold Labrador 
            Current on the western side of the subpolar North Atlantic.



7  Data and Sample Storage and Availability

All meta information, underway, and bathymetric data was sent after the 
end of the cruise to the German Oceanographic Data Centre (DOD). The 
respective cruise summary report is inventoried at DOD under reference 
number 20130051. Already aboard, raw and processed scientific oceanic 
data was merged into the data collections of the University of Bremen and 
BSH Hamburg which facilitates any exchange of data products and results 
among project partners. All scientific data is immediately available to 
project partners and can be obtained on request by interested cooperating 
scientists. Hydrographic data was already exchanged with cooperating 
scientists from the Bedford Institute of Oceanography, Dartmouth, Canada. 
TSG and respective salinometer data obtained during the cruise was sent 
to the Control Station German Research Vessels. Respective staff members 
will forward it to those in charge of taking care of the quality control 
of the vessel’s TSG system.

Scientific data of cruise MSM-28 will be made public and submitted to 
international data centers like the CLIVAR & Carbon Hydrographic Data 
Office (cchdo.ucsd.edu) and PANGAE (www.pangaea.org) in quarter 3 of year 
2016. Both serve as open access long-term archives providing free access 
to the scientific data.



8  Acknowledgements

Cruise MSM-28 was probably one of the longest cruises conducted with RV 
Maria S. Merian. Thus, team spirit, enthusiasm and close cooperation 
between the different scientific teams, and the scientific group and the 
ship's crew cleared the way for the great success of this cruise. For 
this reason, we would like to thank the master of RV Maria S. Merian, 
Ralf Schmidt, and his entire crew for the assistance and support granted 
to us during cruise MSM-28 which made our stay aboard very comfortable, 
even at times of very unfavorable weather and sea state conditions. 
Further thanks goes to the “helping hands” at our home laboratories and 
the agencies (BMBF, the Senatskommission für Ozeanographie, and the 
Leitstelle Deutsche Forschungsschiffe) that provided the necessary ship 
time, funding, and support to pursue all scientific work.






CCHDO Data Processing Notes

•  File Online Carolina Berys
msm28_exchange_ct1.zip (download) #a2c0b 
Date: 2017-12-03 
Current Status: unprocessed


•  File Submission Carolina Berys
msm28_exchange_ct1.zip (download) #a2c0b 
Date: 2017-12-03 
Current Status: unprocessed 
Notes
CTD data in Exchange format


•  File Online Carolina Berys
MM28.SUM (download) #1a64e 
Date: 2016-10-10 
Current Status: unprocessed


•  File Online Carolina Berys
msm28.zip (download) #d4fa2 
Date: 2016-10-10 
Current Status: unprocessed


•  File Online Carolina Berys
msm28.txt (download) #5012b 
Date: 2016-10-10 
Current Status: unprocessed


•  File Online Carolina Berys
msm28_FullCruiseReport.pdf (download) #1b0ae 
Date: 2016-10-10 
Current Status: unprocessed


•  File Submission Reiner Steinfeldt
msm28_FullCruiseReport.pdf (download) #1b0ae 
Date: 2016-09-20 
Current Status: unprocessed 
Notes
RV Maria S. Merian
Cruise MSM28
St. John's - Tromsö
09th May - 20th June

Chief Scientist: Dagmar Kieke

Region:
Subpolar North Atlantic

WOCE lines A02 and AR07W


•  File Submission Reiner Steinfeldt
msm28.txt (download) #5012b 
Date: 2016-09-20 
Current Status: unprocessed 
Notes
RV Maria S. Merian
Cruise MSM28
St. John's - Tromsö
09th May - 20th June

Chief Scientist: Dagmar Kieke

Region:
Subpolar North Atlantic

WOCE lines A02 and AR07W


•  File Submission Reiner Steinfeldt
msm28.zip (download) #d4fa2 
Date: 2016-09-20 
Current Status: unprocessed 
Notes
RV Maria S. Merian
Cruise MSM28
St. John's - Tromsö
09th May - 20th June

Chief Scientist: Dagmar Kieke

Region:
Subpolar North Atlantic

WOCE lines A02 and AR07W


•  File Submission Reiner Steinfeldt
MM28.SUM (download) #1a64e 
Date: 2016-09-20 
Current Status: unprocessed 
Notes
RV Maria S. Merian
Cruise MSM28
St. John's - Tromsö
09th May - 20th June

Chief Scientist: Dagmar Kieke

Region:
Subpolar North Atlantic

WOCE lines A02 and AR07W












