A.   CRUISE NARRATIVE:  ISS02, IR01W, IR03N (WESTERN ARABIAN SEA)

A.1. HIGHLIGHTS

                        WHP CRUISE SUMMARY INFORMATION

         WOCE section designation  ISS02, IR01W, IR03N
Expedition designation (EXPOCODE)  06MT32_1
      Chief Scientist/affiliation  FRIEDRICH SCHOTT/IfM Kiel*
                            Dates  1995 MAR 23 - 1995 APR 26
                             Ship  RV METEOR
                    Ports of call  Djibouti to Muscat, Oman

               Number of stations  CTD: 91        XBT: 45
                                          25°N
            Geographic boundaries  42°E          62°E
                                           2°S
     Floats and drifters deployed  0
   Moorings deployed or recovered  ?

             Contributing Authors  Prof. Friedrich Schott
                                   Monika Rhein
                                   Olaf Plähn
___________________________________________________________________________
                            *Prof. Friedrich Schott
   Institut fuer Meereskunde   Duesternbrooker Weg 20   24105 Kiel    Germany
 Tel. +49-431-600-4100   Fax. +49-431-600-4102   e-mail: fschott@ifm.uni-kiel.de



A.2. SCIENTIFIC PROGRAM

The cruise was designated to derive hydrographic data in the Arabian Sea as part 
of the WOCE-program and to deploy several moorings in the western Arabian Sea.


A.3. PARTICIPANTS

Prof. Friedrich Schott            Chief scientist      IfM Kiel
  fschott@ifm.uni-kiel.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 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 gastight 
glass syringes (Becton and Dickinson). Then 15-25 mL of the samples were 
transfered 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 the CFC-12 component; replicate samples plotted vs 
          profile number.


PERFORMANCE

During the cruise M32/1 the Kiel CFC system worked continuously. Both 
CFC components CFC-11 and CFC-12 had been sampled on 75 CTD stations and 
880 water were analyzed.

The accuracy was checked by measuring about 220 water samples twice or 
more. It was found to be for CFC-12 1.3% or 0.005 pmol kg-1 (Figure 1). 
The CFC-11 component could not be analyzed successfully (see para 
'Contamination').

The mean blank of the sample transfer and the measurement procedure was 
determined by degasing 1-2 mL of CFC free deep water. During the cruise 
it was in the order of 0.005 pmol kg-1 for CFC-12. Furthermore, CFC free 
water was created by degasing 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 for the CFC-12 component. During 
the cruise the efficiency decreased only 20% (Figure 2). 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

During the whole cruise, the CFC-11 measurements were deteriorated by 
contami- nation of the water bottles. Neither the numerous cleaning 
procedures of the water bottles/rosette nor the replacement ofwater 
bottles did remove the exceptionally high and variable contamination for 
CFC-11. For instance, the CFC-11 saturation in surface water was between 
135-180%. The CFC-12 concentrations presumably remained unaffected, with 
surface saturations between 95 and 110%. On some stations, the CFC-12 
peaks were disturbed by the high N2O levels, these data were removed.


COMMENTS

The CFC concentrations decrease exponentially from the surface to about 
1000 m depth. At greater depths, CFC concentrations were below detection 
limit (Figure 3). In the western Gulf of Oman (stations 210-224) the 
CFC-12 concentrations in the density range of the PGW (Persian Gulf 
Water, 26.3<SIGMAtheta<26.8) were up to three times higher than in 
ambient surface water (Figure 3). The saturations reached 270% (Figure 
4), which is usually not observed in the ocean [Rhein et al., 1997b]. 
The supersaturations were not caused by contamination of the Niskin 
bottles, syringes, or of the CFC purge and trap system. Different 
bottles and syringes were used to sample the signal on each station and 
samples were taken from the respective bottles and syringes in depths 
not affected by the CFC maximum. The PGW was probably contaminated in 
the Persian Gulf, as the signal was restricted to the density of the PGW 
and the outflow


FIGURE 3: All CFC-12 concentrations measured during the cruise M32/1 
          versus depth. The samples collected in the Gulf of Aden are 
          marked bycrosses (x) and the data from the Gulf of Oman are 
          marked by circles (o).


region in the Gulf of Oman [Plähn et al., 1999]. The signal was also 
observed during the Knorr cruise 145, in August 1995 (R. Fine, RSMAS 
Miami, USA) and during the Sonne cruise 128, in January 1998 (O. Plähn 
and M. Rhein, IFM Kiel, Germany).

In the Gulf of Aden the CFC-12 saturation in the Red Sea Water (SIGMA 
theta ~ 27.2) was determind to be 65% near the Strait of Bab el Mandeb 
[Rhein et al., 1997a]. However, this signal decreased eastward and only 
20% of the source signal could by found near the island of Socotra, 
which is in good agreement with the dilution of the salinity signal 
[Plähn, 1999]. In September 1995 the out ow of the Red Sea was 
investigated during the Knorr cruise 145, too (M. Warner, Seattle, USA). 
During that cruise the largest CFC-12 saturation in the RSW was only 
about 40% [Mecking and Warner, 1999]. The reason of this difference is 
caused by the variable ow field in the Strait of Bab el Mandeb. In the 
Arabian Sea the saturation decreased southward to about 1.5-3.5% 
southern of 8

Outside the Gulf of Aden and Gulf of Oman the CFC-12 saturation, within 
the density range of the PGW (26.3< SIGMA theta <26.8), was between 15 
and 30%. At some stations (No. 146, 149, 170, and 217) a CFC-12 
saturation at the surface of more than 108% was found (Figure 5). The 
reason of this anomaly is unknown. These supersaturations are not 
correlated with the SST (sea surface temperature) and the samples are 
not in uenced by a N2 O peak. Thus it is assumed that they are real.


FIGURE 4: Saturation of all measured CFC-12 concentrations during the 
          cruise M32/1 versus density.


FIGURE 5: CFC-12 surface saturation measured during the cruise M32/1.


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.

Mecking, S. and M.J. Warner (1999). Ventilation of Red Sea Water with 
    respect to chloro uorocarbons. J. Geophys. Res., 104, S. 
    11087-11097.

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

Plähn, O., M. Rhein, R.A. Fine, and K.F. Sullivan (1999). Pollutants 
    from the Gulf War serve as water mass tracer in the Arabian 
    Sea. Geophys. Res. Lett., 26, S. 71-74.

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

Rhein, M., L. Stramma, and O. Plähn (1997b). Tracer signals of the 
    intermediate layer of the Arabian Sea. Geophys. Res. Lett., 
    24, S. 2561-2564.


APPENDIX

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

o  The station file 'meteor321.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 'meteor321.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 ag 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
__________________________________________________________________________
Precision                           CFC-12 10%
Accuracy                            CFC-12: 1.3%
Blanks                              CFC-12: 0.005 pmol kg-1



WHPO DATA PROCESSING NOTES:
     
Date      Contact     Data Type  Data Status Summary
--------  ----------  ---------  --------------------------------------------
05/08/00  Rhein       CFCs       Data are Public
          06MT32_1
          06MT32_6
          can be made public and included in the CD_ROM

10/03/02  Uribe       SUM, CTD   Website Updated; Exchange file online
          o  Casts changed to match SUM
          o  CTD was converted to exchange. 
          o  CTD Casts were changed from increasing order to match the sumfile. 
          o  All data still Encrypted. No update on status.

03/20/03  Stramma     CTD/BTL    Website Updated; Data are public
          I saw that there are three references with CTD and bottle data listed 
          as non-public. These are:
          o  06MT32_1
          o  IR03N 06MT32_1
          o  IR03N 06MT32_6
          We like to ask you to make these data public.

03/26/03  Bartolacci  CTD/BTL    Data are Public; Files unencrypted
          I have unencrypted the bottle and ctd files for this cruise. Completed 
          minor edits on the bottle file (column alignment and header asterisk 
          ajustments as well as expocode correction) in order to create exchange 
          and netCDF files. With help from Karla there are now netCDF ctd files 
          as well. All are now public, as per Dr. Strama (for Dr. Schott). 
          However, please note that there is still no documentation for this 
          cruise. Emails will be sent requesting a cruise doc.

07/01/03  Kappa       DOC        PDF & Text reports assembled
          Both PDF and Text docs contain:
          o  Cruise summary information
          o  CFC Report
          o  These WHPO Data Processing Notes
          PDF report also contains:
          o  Figures for CFC report
          o  Cruise Track
          o  Links to Figures from text references


