A.   CRUISE NARRATIVE:  ISS02, IR03N (WESTERN ARABIAN SEA)

A.1. HIGHLIGHTS

                        WHP CRUISE SUMMARY INFORMATION

                 WOCE section designation  ISS02, IR03N
        Expedition designation (EXPOCODE)  06MT32_4
              Chief Scientist/affiliation  Quadfasel/IfMH*
                                    Dates  1995 JUN 8 - 1995 JUL 12

                                     Ship  RV METEOR
                            Ports of call  not reported

                       Number of stations  CTD: 102
                                                    18°N 
                    Geographic boundaries     50°E         60°E
                                                     3°S

             Floats and drifters deployed  not reported
           Moorings deployed or recovered  not reported

                     Contributing Authors  Dr. Detlef R. Quadfasel
                                           Monika Rhein
                                           Olaf Plähn
____________________________________________________________________________________
                              *Dr. Detlef R. Quadfasel                              
       Institut für Meereskunde   Troplowitzstraße 7   22529 Hamburg  Germany
Tel. +49-40-4123-4206   Fax. +49-40-4123-4644   e-mail: quadfasel@ifm.uni-hamburg.de



A.2. SCIENTIFIC PROGRAM

The cruise was designated to derive hydrographic data in the Arabian Sea as part 
of the WOCE-program.


PARAMETERS REPORTED

  SALNTY  
  OXYGEN
  SILCAT
  NITRAT
  NITRIT
  PHSPHT
  CFC-11
  CFC-12
  TCARBN
  PH



A.3. PARTICIPANTS

Dr. Detlef R. Quadfasel           Chief scientist      IfM Hamburg
  quadfasel@ifm.uni-hamburg.de
------------------------------------------------------------------
Monika Rhein                      Chlorofluorocarbons  IfM Kiel
  monika.rhein@io-warnemuende.de
------------------------------------------------------------------
Olaf Plähn                        Chlorofluorocarbons  IfM Kiel
  oplaehn@ifm.uni-kiel.de
------------------------------------------------------------------
Martina Elbrächter                CFC-Lab              IfM Kiel
  melbraechter@ifm.uni-kiel.de

IfM Hamburg: Institut für Meereskunde, 22529 Hamburg, Germany
   IfM Kiel: Institut für Meereskunde, 24105 Kiel,    Germany
 


B.  CHLOROFLUOROCARBONS
    (Monika Rhein and Olaf Plähn)

REGION: Arabian Sea, Gulf of Aden, Gulf of Oman,


SAMPLE COLLECTION AND TECHNIQUE

All samples were collected from 10 L Niskin bottles. The bottles had been 
cleaned prior to the cruise using isopropanol. All 'O' rings, valves, and taps 
were removed, washed in isopropanol and baked in a vacuum oven for 24 hours. The 
rubber bands on all bottles were replaced by stainless steel springs. The 
personnel for all water sampling and handling procedures at the bottles wore 
one-way gloves to protect the valves from grease.

About 100 ml of water were taken from the water bottles with gas-tight glass 
syringes (Becton and Dickinson). Then 15-25 ml of the samples were transferred 
to a purge and trap unit and analyzed on board following the procedures 
described in Bullister and Weiss [1988]. The CFCs were separated on a packed 
stainless steel column filled with Porasil C and detected with an Electron 
Capture Detector (ECD). The carrier gas was ECD pure Nitrogen, which was 
additionally cleaned by molsieves (13X mesh 80/100).

The calibration was done using a standard gas with near air concentrations to 
convert the ECD signal in concentrations. The CFC values are reported in pmol 
kg-1 on the SIO93 scale (R. Weiss, SIO).


Figure 1: Accuracy of CFC-12 (o) and CFC-11 (*); replicate samples plotted vs. 
          profile number.


PERFORMANCE

During the cruise M32/4 the Kiel CFC system worked continuously. Both CFC compo- 
nents CFC-11 and CFC-12 had been sampled on 100 CTD stations and 1290 water sam- 
ples were analyzed. The accuracy was checked by measuring about 220 water 
samples twice or more (Figure 1). It was found to be for CFC-12 1.3% or 0.007 
pmol kg-1 and for CFC-11 1.2% or 0.006 pmol kg-1 .

The mean blank of the sample transfer and the measurement procedure was 
determined by degassing 1 - 2 ml of CFC free deep water. During the cruise it 
was in the order of 0.004 pmol kg-1 for both components. Furthermore, CFC free 
water was created by degassing 5 L of seawater with ECD-pure nitrogen gas, to 
determine blanks of the measurement system and the syringes. Analysis of 25 ml 
of blankwater resulted in concentrations below 0.007 pmol kg-1 for both 
components.

The efficiency of the ECD was stable in time for both components (Figure 2). The 
temporal variations were only 15%. Relative to the start of the cruise the 
sensitiveness for the CFC-11 component first increased to 105%, decreased to 90% 
and increased again to about 95%. The CFC-12 component showed a decrease from 
100% to less than 90% during the cruise. To correct the temporal drift of the 
ECD, a calibration curve with seven different gas volumes was taken before and 
after each station. The temporal change between two calibration curves was 
assumed to be linear in time. CFC concentrations were calculated by using the 
two neighboured points, supposing that the calibration curve is linear between 
these points.


Figure 2: The temporal evolution of the ECD-efficiency during the cruise for the 
          0.5 ml volume (small) and the 2 ml volume (large).


CONTAMINATION

At the end of the cruise painting work inside the vessel lead to contamination. 
Due to this activity three profiles (at most Station-No. 365) were disturbed by 
high CFC concentration of the laboratory air. On some stations, the CFC-12 peak 
was disturbed by the high N2O levels of the samples. 


COMMENTS 

At station 353 some bottles did not close, the profile was repeated down to 150 m. 
The second cast got the same station number, but the bottles were counted from 
201-224 in the data-file 'meteor324.sea'.

              'meteor324.sea' and the file 'meteor324.sum'.

The CFC concentrations decreased exponentially from the surface to about 1000 m 
depth (Figure 3). At larger depths, CFC concentrations were below detection 
limit. During this cruise the southwest monsoon started with wind-velocities up 
to 20 m s-1 . This strong wind forcing induced an intensive mixing of the upper 
layer, followed by a decrease of the sea surface temperature (SST) and the CFC 
surface saturation [Rhein et al., 1997]. The mean saturation was 92% for CFC-11 
and 87% for CFC-12 (Figure 4). Higher values of the CFC-11 components compared 
to the CFC-12 saturation are caused by different velocities of the gas-exchange. 
At 400m depth the saturation of CFC-11 is only 0.4% higher than CFC-12 and at 
800 m depth the saturations are equal. At the northern edge of the 'Great Whirl' 
(Stat. 319) and at the coast off Oman (Stat. 353) extremely low surface-
saturations were measured, caused by upwelling processes [Plähn, 1999]. The mean 
CFC-11/CFC-12-ratio (Figure 5) increased from the surface (CFC-11/CFC- 12 ~ 1.8) 
down to 900 m (CFC-11/CFC-12>2.0). The accuracy of the ratio is less than 0.1 if 
the CFC-11 concentration it larger than 0.15 pmol kg-1 . For lower 
concentrations the error of the ratios increase.


Figure 3: All CFC-11 concentration measured during M32/4 versus depth.



REFERENCES

Bullister, J.L. and R.F. Weiss (1988). Determination of CCl3F and CCl2F2 in 
    seawater and air. Deep-Sea Res., 35, S. 839-853.

Plähn, O. (1999). Ventilation und Zirkulation in der Arabischen See: Ergebnisse 
    aus Beobachtungen und Modellanalysen. Dissertation, Universität Kiel.

Rhein, M., O. Plähn, and L. Stramma (1997a). Tracer distribution in the Arabian 
    Sea, 1995. WOCE Newsletter, 27, S. 12-14.


Figure 4: CFC-11 (green) and CFC-12 (red) saturation at the surface

Figure 5: CFC-11/CFC-12 ratio versus density



APPENDIX

o  Leg 4 is part of the 1995 Kiel CFC data set including the M32 legs 1 and 6 in
   the Arabian Sea.

o  The station file 'meteor324.sum' includes:
   1  station number
   2  year
   3  month
   4  day
   5  hour: minutes in decimal system
   6  latitude: minutes in decimals
   7  longitude: minutes in decimals
   8  water depth (m)
   9  depth of CTD profile (m)

o  The bottle file 'meteor324.sea' includes:
   1  station number
   2  bottle number
   3  depth (dbar)
   4  in-situ temperature (°C)
   5  salinity (psu)
   6  CFC-12 (pmol kg-1)
   7  CFC-11 (pmol kg-1)
   8  WOCE quality flag for CFC-12 and CFC-11


TECHNICAL INFORMATION

Gas chromatograph                   Shimadzu GC 14
GC column                           stainless steel, packed with Porasil C
Cooling trap                        with Porapak T and Porasil C
Trap temperatures                   30°C, 100°C
Column temperature                  70°C, isothermal
ECD temperature                     300°C
Electron capture detector           Shimadzu
Software for chromatogram analysis  Shimadzu C-R4A
Standard gas                        ALM 83959, R. Weiss, SIO
--------------------------------------------------------------------------
Accuracy                            CFC-11: 1.3% , CFC-12: 1.2%
Blanks                              CFC-11: 0.004 pmol kg-1, 
                                    CFC-12: 0.004 pmol kg-1


WHP DATA PROCESSING NOTES:


Date      Contact    Data Type  Data Status Summary
--------  ---------  ---------  ------------------------------------------------
08/16/95  Quadfasel  SUM        Submitted
11/05/96  Quadfasel  CTD        Submitted
11/05/96  Quadfasel  BTL        T/S/O, NUTs, CFCs, TCARBN Submitted
12/17/99  Rhein      CFCs       Doc submitted
04/23/01  Bayer      He/Tr/C14  Measured, Not Submitted
          The data (we) received from Meteor cruise 32, leg 4 to the Indian 
          Ocean have not been sent yet. However, the data (about 150 tritium, 
          270 helium and 70 AMS-C14) are available in a laboratory internal 
          format. The person responsible for this cruise is still around here 
          and plans to merge the data to the hydrographic data (WHP format) 
          including quality flags by summer/fall 2001. If this is not ok for you 
          and you prefer to have the data on short notice we surely will be able 
          to send them in a format similar to the one used for the Hjort 1994 
          cruise.

          YES, ALL OUR DATA SUBMITTED TO WHPO ARE PUBLIC!
