Preliminary data report
March 28, 1995


A.     Cruise Narrative  


A.1    Highlights

A.1.a  WOCE Designation           AR06, AR16

A.1.b  Expedition Designation:    EXPOCODE 06HF2092_1
                                           06HF2092_2
                                           06HF2092_3

A.1.c  Chief Scientist:  Leg 1-3: John Hans-Christian
                                  Biologische Anstalt Helgoland
                                  Martin-Luther-King-Platz 3
                                  Hamburg, Germany  20146
    
A.1.d  Ship:  R/V Heincke

A.1.e  Ports of Call:    Leg 1:   Cuxhaven,Germany to Lisboa,Portugal
                         Leg 2:   Lisboa to Leixoes,Portugal
                         Leg 3:   Leixoes to Cuxhaven

  
A.1.f  Cruise Dates:     Leg 1:   January 3 to January 20, 1992
                         Leg 2:   January 21 to January 29, 1992
                         Leg 3:   January 31 to February 6, 1992           


A.2    Cruise Summary

A.2.a  Text giving georgraphic boundaries

A.2.b  Total Number of Stations Occupied

During the cruise a total of 114 CTD/rosette stations were occupied using a  
CTDO equipped with a 12 position rosette with 2.7 l Teflon-type water sampling
bottles.

  o CTDO and Speed of Sound
  o Salinity and oxygen of water samples
  o Temperature and pressure by reverse deep sea thermometers

A.2.c  Floats and drifters deployed

A.2.d  Moorings deployed or recovered


A.3    Principal Investigators

Name      Responsibility  Institution
E. Hagen  CTDO,S,O2,      IOW*

*See table 1 for address of Institution


A.4    Scientific Programme and Methods
A.5    Major Problems and Goals not Achieved
A.6    Other incidents of Note
A.7    List of Cruise Participants
	

Table 1:  List of Cruise Participants

Name              Responsibility  Institution
-----------------------------------------------
Stefan Weinreben  CTD-Software    IOW
Rainer Bahlo      CTD Hardware    IOW
Wolfgang Hub      Salts, Oxygen   IOW
-----------------------------------------------
IOW               Institut fuer Ostseeforschung 
                  Warnemuende, Germany
                  d-18119


B     Underway Measurements

B.1   Navigation and Bathymetry
B.2   Acoustic Doppler Current Profiler (ADCP)
B.3   Thermosalinograph and underway dissolved oxygen, fluorometer, etc.
B.4   XBT and XCTD
B.5   Meteorological Observations
B.6   Atmospheric Chemistry


C     Measurement Techniques and Calibrations

During the cruise one CDTO probe was used.

Description of the CTDO (WLOST 1993):
The CTDOs and the sensors are manufactured at the Institut fuer
Meereskunde Warnemuende (IfMW), Germany.  The CTDO is an OM-87 =
Oceanolographic Measuring System, consisting of an expandable dividing
CTDO-probe, interfaced through a special designed slave-computer, a
meteorological subsystem interfaced by a second slave-computer and a
master-PC.  The IfMW began to develop oceanographic measuring systems
in the 60s.  The first computer controlled CTD-system, OM-75 (MOECKEL
1980) was taken into service in 1976.  The new generation: OM-87 has
been used since 1988.

The CTD is equipped with frequency-analogous sensors at standard ports,
developed and manufactured by IfMW; the oxygen sensor together with FSI
"Kurt Schwabe", Meinsberg, Germany.


Table 2: CTDO - Sensor Configuration List
-------------------------------------------------------------
CTD  Stat. No.  Parameter       sensor  resolution  precision
-------------------------------------------------------------
2    124        pressure        p250    0.1 dbar    2 dbar
                temp            t121    0.0015 K    0.01 K
                conductivity    c884    0.0008mS/cm
                speed of sound  v218    0.025 m/s   0.3 m/s
2    113        oxygen          o020    0.01 ml/l   0.1 ml/l
114  124        oxygen          o028    0.01 ml/l   0.1 ml/l
------------------------------------------------------------


C.1.b  CTDO Sampling procedure and data processing

Sampling procedure

CTDO was recorded on hard disk during the down casts.

sampling rate:               1 record in 1.2 s =0.83 Hz.
integration time of sensors: 1s
lowering speed of CTD:       1.0 m/s
time constants:              pressure and temperature sensors = 0.1 s
                             conductivity sensor = 0.1 s at 1 m/s lowering speed

The precalibration constants of pressure, temperature, conductivity,
sound speed sensors and the recalibration constants of the oxygen
sensors were used over the whole cruise.  The check measurements of
CTDO and water sample data (in situ comparisons) were used for
calculating the post-cruise corrections.

Post-Cruise Data Processing

The raw data are digitized frequencies, which had been converted to
physical units of pressure, temperature, conductivity, oxygen and sound
speed.

A validation routine was applied to the CTDO down cast data ( Lass et.
al. 1983), to eliminate:

   o Data values, which are not physically realizable
   o Random errors by recursive low-pass filtering (Acheson 1975)
   o Systematic errors: Caused by the effect of the ship's 
     rolling and pitching on the lowering rate of CTD.  Records
     acquired while CTD is moving down too slowly have been 
     discarded to enforce a strick monotonic sequence in pressure.

The so called eddy-algorithm in connected view with the values of sensor
integration time and lowering rate reduced the effect of different time
lags of the sensors to minor importance.

The calculation of salinity from conductivity and conversion of
dissolved oxygen from volumetric to weight concentration were done last
after correcting the data as described below.  Dissolved oxygen was
converted according to WOCE O.M. (1991).

The data have not been averaged finally in 2 dbar increments because of
the low sampling rate of the CTD and a great amount of discarded
records in the course of data processing up to 50 pc on average.

Post-Cruise CTD Data Corrections

In order to get the CTDO to match the water sample data, following fits
were applied to CTDO:


Table 3:
-----------------------------------------------------------------------
CTDO  Stat. No.  Sensor         Fitting Param.   Fitting Polynoms
-----------------------------------------------------------------------
                 Pressure       Linear fit       Pres(fitted)=A0+A1*PRES
                                A0        A1
   2     124     P250          -1.5       0.99768

                 Temp.          Linear Fit       Temp(fitted)=A0+A1*TEMP
                                A0        A1
   2     124     T121           0.01156   0.997985


                 Conductivity time depended correction
                                                 Cond(corr)=COND+A0+A1*time
                 Time/hours=beginning time of cast (in continuously
                 counted hours of the year: Jan 1; 0 o'clock:Time=0hrs)

                                A0        A1
   2      11     C884           0.07203  -6.08E-4
  12      36                   -0.27562   6.59E-4
  40     118                    0.13979  -3.53E-4

                 Conductivity:  Linear Fit:      Cond(fitted)=A0+A1*cond
 119     124     C884          -5.77E-2   1.0

                 Oxygen         Linear Fit       Oxyg(fitted)=A0+A1*oxyg
                 (ml/l)         A0        A1
   2     112     o020           0.0       0.1677

                 Oxygen pressure correction
                 ml/l                            Oxyg(corr)=Oxyg(fitted)+A0+A1*pres
                                A0        A1
   2     112     o022          -0.66      0.1677
 114     118     o028          -0.6926    4.1E-4

                 Oxygen: data discarded
 113             o020
 119     124     o028

                 Speed of sound: no fit
   2     124     V218
--------------------------------------------------------------------------


C.1.d  Errors and Noise

During the cruise located faulty sensors were replaced as listed above
in the CTD sensor configuration list.  Station 113 o020 sensor failed
and was changed.  Station 119-124 o028 sensor also failed.

C.2    Water Sampling for In Situ Comparisions

C.2.ab Techniques and sampling procedures

After finishing the down cast (CTDO-recording), the CTD was lifted and
stopped within well mixed layers.  After 10 minutes waiting to let the
deep-sea thermometers adapt to the surrounding temperature two water
bottles were tripped while a short time CTDO recording.  The deep sea
thermometers (2 protected and 2 unprotected) were reversed
simultaneously with the first bottle tripping.

When the first bottle of each sampling depth tripped correctly the
water samples ( 2 dissolved oxygen and 2 salinity) were drawn from
these bottles, otherwise from the second ones.

The S and O data of the water samples so as the reverse temperature and
-pressure data were used for the post-cruise corrections of the CTDO data.

Salinity

The water sample salinity were measured with a Guildline Autosal
Modell 8400A salinometer, manufactured by Guildline Instruments Ltd.,
Smiths Falls, Canada.  The salinometer was standardized weekly with
I.A.P.S.O. Standard Seawater (SSW) Batch P 115.  Differences in
standardization readings were less than 3.

The salinometer manufacturer claims a precision 0.002 and an accuracy
of better than 0.003; better than 0.001 when the laboratory temperature
is constant (+/- K) and about 1-2 K below the bath temperature of the  
salinometer.

Oxygen

The dissolved oxygen samples were analyzed by the Winkler Titration
Method modified by Carritt and Carpenter (1966).

Temperature (reverse thermometers)

The following reverse thermometers were used

VEB Thermometerwerk Geraberg, Germany
                    Scale         Graduated in
pressure protected  -2...+30degC  0.1K
unprotected         -2...+30degC  0.1K
----------------------------------------------

Gohla-precision, Kiel, Germany
                    Scale         Graduated in
pressure protected  -1...+35degC  0.1K
----------------------------------------------

Duplicate Water Samples

Two or three duplicate salinity and oxygen samples were drawn from
bottle.  The differences between the salinity and oxygen measurements
of the duplicate water samples and the standard deviation of the
differences are shown in the table 4.


Table 4:
          average differences   max diff    std. dev
          between samples        of all differences
----------------------------------------------------
salinity  0.0019 psu            0.014 psu   0.0022
oxygen    0.027 ml/l            0.1 ml/l    0.0228
----------------------------------------------------


C.2.f  Laboratory and Sample Temperatures

The laboratory was temperature controlled: 19...22 deg C.  The bath
temperature of the Autosal salinometer was set to 24 degC.  Salinity
and oxygen samples had been tempered at room temperature when measured.
 
C.2.I  Standards used

I.A.P.S.O Standard Seawater, Batch p115, 6.2.91 during the cruise this
was the only batch used.


D.     Acknowledgments
E.     References

Acheson, D.T., 1975.  Data Editing--Subroutine EDITQ.  NOAA Technical
     Memorandum EDS CEDDA-6.

Lass, H.U., Wulff, C., Schwabe, R., 1983. Methoden und Programme zur
     automatischen Erkennung und Korrektur von Messfehlern in
     ozeanologischen Vertikalprofilen.  Beitrage zur Meereskunde, Heft 48,
     pp 95-111, Berlin.

Moeckel, F., 1980.  Die ozeanologische Messkette OM 75, eine
     universelle Datenerfassungsanlage fuer Forschungsschiffee.  Beitraege
     zur Meereskunde, Heft 43, pp 5-14, Berlin.

Unesco, 1983. International Oceanographic tables. Unesco Technical Papers in 
     Marine Science, No. 44.

Unesco, 1991. Processing of Oceanographic Station Data, 1991. By JPOTS
     editorial panel.

Wlost, K.-P., 1993.  The OM-87-System: a brief description.  Institut
     of Baltic Reasearch Warnemnde, Germany. unpublished paper.

WOCE Operations Manual, Vol. 3, Sec.3.1, Part 3.1.2, 1991. WHP Office
     Report WHPO 90-1, WOCE Report No. 67/91, Woods Hole, Mass., USA.

WOCE Operations Manual, Vol. 3, Sec 3.1, Part 3.1.3:  WHP Operations
     and Methods; C.H. Culberson:  Dissolved Oxygen, WHP Office Report WHPO
     91-1, WOCE Report No. 68/91,1991, Woods Hole, Mass., USA.


F.   WHPO Summary

Several data files are associated with this report.  They are the ebc4.sum, 
ebc4.hyd, ebc4.csl and *.wct files.  The ebc4.sum file contains a summary of
the location, time, type of parameters sampled, and other pertient
information regarding each hydrographic station.  The ebc4.hyd file contains the
bottle data. The *.wct files are the ctd data for each station.  The *.wct 
files are zipped into one file called ebc4.wct.zip. The ebc4.csl file is a 
listing of ctd and calculated values at standard levels.

**NOTE**  The preliminary *.csl files were not created due to the CTD data
being provided in non-uniform levels


G.   Data Quality Evaulation
