Preliminary data report
March 28, 1995

A. Cruise Narrative

A.1 	Highlights

A.1.a 	Expedition Designation AR16/AR06

A.1.b	 EXPOCODE:	07AL991/1 through /4

A.1.c 	Chief Scientist:	Eberhard Hagen, IfMW

A.1.d	 Ship:			R/V   A.V.Humboldt

A.1.e	 Ports of Call:	Leg 1: Rostock, Germany to Lisboa, Portugal
Leg 2: Lisboa to Casablanca, Marocco
Leg 3: Casablanca to Lisboa  
Leg 4: Lisboa to Rostock

A.1.f 	 Cruise Dates:	Leg 1: August 20 to August 30, 1991
Leg 2: September 2 to September 13, 1991
Leg 3: September 17 to October 15, 1991
Leg 4: October 18 to October 25, 1991

A.2  Cruise Summary

A.2.a	Geographic boundaries

A.2.b	Number of stations occupied
  
During the cruise a total of 196 CTD/rosette stations were occupied using a CTDO 
equipped with a rosette of 12*2.7 l teflon-type water sampling bottles.

 o	CTDO and sound speed;
 o	salinity and oxygen of water samples;
 o	temperature and pressure by reverse deep sea thermometers
 o	air-pressure, temperature, humidity up to an attitude  
  	of about 30 km by radiosondes: 56 starts
 o	stepwise current meter profiling (0-500 m) using  
 o	GPS navigation system: 58 stations
 o	temperature/salinity in 2 m depth between stations           
  	continuously: 54 days
 o	skin-SST by means of Heiman KT4 radiometer (10-12 *10**-6 m): 54 days
 o	meteorological standard parameters: 54 days
 o	pyranometer: 54 days

A.3 Principal Investigators

Table 1: Principal Investigators*

Name				Responsibility			Institution
E. Hagen			CTDO,S,O2,Current Profiles	IfMW
R.Feistel			SST					IfMW
E.Mittelstaedt		Currents				BSH

* See Table 2 for list of Institutions
Table 2: List of Institutions
Abbreviation	Institution

BAH			Biologische Anstalt Helgoland
			Martin-Luther-King-Platz 3
			Hamburg, Germany  20146

BSH			Bundesamt fuer Seeschiffahrt und
			Hydrographie
			Postfach 30 12 20 
			Hamburg, Germany D-20305

IfMW			Institut fuer Meereskunde Warnemunde
			Seestr. 15
			D-18119 Rostock-Warnemande
			Germany

IOW			Institut fuer Ostseeforschung 
			Warnemuende, Germany
			d-18119


A.4 Scientific Programme and Methods

A.5 Major Problems

The CTD data of station 252-253 were disturbed and have been discarded.
At station 276 the OM-87 probe No 1 was lost during the up cast when the 
cable parted. From station 277 to 434 the OM-87 probe No 2 was used.

A.6	Other Incidents of Note


A.7	List of Cruise Participants

Table 3: List of Cruise Participants

Name				Responsibility				Institution*

Leg 1-4

Eberhard Hagen		Chief Scientist, radiosondes starts	IfMW(IOW)
Stefan Weinreben		CTD-Software				IfMW(IOW)
Henry Will 			CTD-Hardware, current profiling	IfMW(IOW)
Rainer Feistel		Skin-Bulk-SST				IfMW(IOW)
Christoph Zuelicke	Skin-Bulk-SST				HUB
Guenter Plueschke		Salts, CTD Winch				IfMW(IOW)
Wolfgang Hub		Oxygen, CTD Winch				IfMW(IOW)
Dieter Fritsch		Precision Mechanics			IfMW(IOW)

Leg 1-2

Holger Klein		Moorings					BSH
Holger Giese		Moorings					BSH

Leg 4

Guido Schmuck		Skin-Bulk-SST				IRSA

*See Table 2 for list of Instituions


B.	Underway Measurements

B.1	Navigation and bathymetry
B.2	Acoustic Doppler Current Profiler (ADCP)
B.3	Thermosalinograph 
B.4	XBT and XCTD
B.5	Meteorological observations
B.6	Atmospheric chemistry

C.	Hydrographic Measurements

C.1	CTDO

The CTDO and the sensors are manufactured at the institu fuer Meereskunde 
Warnemuende, Germany.  The CTDO is an OM-87 = Oceanological 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 meteorological subsystem interfaced by 
a second slave-computer and a master-PC.  The IfMW began to develop 
oceanographic measuring systems in the 1960's.  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.

C.1.a	Sensor Configuration List

The various sensors used on the different CTDs are listed in Table 3 by station 
and CTD number. 

Table 4:  CTD sensor configuration
CTD/Stat. No. 
Parameter
Sensor
Resolution
Precision





CTD No. 1/Sta. 240-276
Pressure
P251
0.1 dbar
2 dbar
CTD No. 2/Sta. 277-311
Pressure
P600
0.2 dbar
5 dbar
CTD No. 2/Sta. 312-342
Pressure
P252
0.1 dbar
2 dbar
CTD No. 2/Sta. 343-434
Pressure
P601
0.2 dbar
5 dbar





CTD No. 1/Sta. 240-276
Temp
T102
0.0015 K
0.01 K
CTD N0. 2/Sta. 277-434
Temp
T106
0.0015 K
0.01 K





CTD No. 1/Sta. 240-251
Conductivity
C854
0.0008 mS/cm

CTD No. 1/Sta. 254-276
Conductivity 
C858
0.0008 mS/cm

CTD No. 2/Sta. 277-311
Conductivity
C854
0.0008 mS/cm

CTD No. 2/Sta. 312-434
Conductivity
C884
0.0008 mS/cm






CTD No. 1/Sta. 240-276
Oxygen
O022
0.01 ml/l
0.1 ml/l
CTD No. 2/Sta. 277-295
Oxygen
O027
damaged

CTD No. 2/Sta. 312-325
Oxygen
O023
damaged






CTD No. 1/Sta. 240-276
Speed of Sound
V216
0.025 m/s
0.3 m/s
CTD No. 2/Sta. 277-279
Speed of Sound
V217
0.025 m/s
0.3 m/s
CTD No. 2/Sta. 280-311
Speed of Sound
V217
damaged



All sensors were calibrated before the cruise at the calibration
laboratory of IfMW.  The oxygen sensor was recalibrated during the cruise at the 
first station with water samples.  The calibration constants of all sensors were 
checked up by the in situ comparisons of p, T, C, O2.  


B.1.b  	CTDO

The down cast data were recorded on hard disk.

Sampling rate: 1 record in 1.2s = 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 calibration constants of pressure, temperature, conductivity, sound speed 
sensors and the recalibration constants of the oxygen sensor 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.

B.1.c	Post-Cruise CTD 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: 
1. data values, which are not physically realizable.

2. Random errors by recursive low-pass filtering (Acheson, 1975).

3. Systematic errors caused by the effect of 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 strict
   monotonic sequence in pressure.  The so called eddy-algorithm in
   connected view with the values of sensor integration time and lowering
   rate reduce the effect of different time lags of the sensors to minor
   importance. 

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

The data haven't 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% on average.

C.1.d	CTD Post-Cruise Corrections

In order to get the CTDO to match the water sample and, respectively, the 
thermometer data that following fits defined in Table 5 were applied to the CTDO 
data.


Table 5: CTD calibration Coefficients
-------------------------------------------------------------------------
CTD No./Sta. No.	Sensor	Fitting		Fitting
					Parameter	Polynomials
-------------------------------------------------------------------------
                	pressure	linear fit      PRESfitted=A0+A1*PRES
                        		A0       A1
  240-251       	P251    	3.8      1.006
  254-276       	P251    	3.8      1.006

                	pressure: data discarded
 
  252-253       	P251

                	pressure: temperature correction
                                         	    PREScorr.=PRES+A0+A1*TEMP
                        		A0       A1  
  277-311       	P600    	36.2    1.38

                	pressure: linear fit:     	PRESfitted=A0+A1*PRES
                        		A0       A1
  312-342       	P252     	1.41    1.019
  343-434       	P601    	30.44    0.96943

	Temperature: no fit; measured data were of higher quality than
	the thermometer data

  240-251       	T102                       
  254-276       	T102                  
  277-434       	T106

                	temperature: data discarded
  252-253       	T102

                	conductivity: pressure correction:
                                         	CONDcorr.=COND+A0+A1*PRES
                        		A0         A1
  240-251       	C854    		-7.315E-2  7.409864E-5

                	conductivity: data discarded
  252-253       	C853

                	conductivity: time dependend correction
                                         CONDcorr.=COND+A0+A1*TIME
  TIME/hours=Beginning time of cast(in continuously caunted
             hours of the year: January 1; 0 o'clock:
                                                   TIME=0 hours)
                        		A0        A1                    
  254-268       	C858    	13.03789  -2.20388E-2
  269-276       	C858    	-1.30243   2.178216E-4

                	conductivity: quadratic fit:
                                   CONDfitted=A0+A1*COND+A2*COND**2
                        		A0        A1        A2
  277-311       	C854    	1.8108    0.921699  8.507983E-4

             		conductivity: time dependend correction
                                         CONDcorr.=COND+A0+A1*TIME
  TIME/hours=Beginning time of cast(in continuously caunted
             hours of the year: January 1; 0 o'clock:
                                                   TIME=0 hours)
                        		A0          A1
  312-339       	C884      	9.41769   -1.496255E-3
  340-350       	C884          -42.25939    6.661E-3
  351-381       	C884      	1.72513   -2.265E-4
  382-426       	C884           -2.18171    3.68E-4
  427-434       	C884           -1.410598   2.52E-4

                	oxygen: linear fit:       OXYGfitted=A0+A1*OXYG
                	(ml/l)  	A0       A1
  240-251       	O022    	0.654    0.9744
  
                	oxygen: pressure correction
                                      OXYGcorr.=OXYGfitted+A0+A1*PRES
                	(ml/l)  	A0       A1
  254-276       	O022    	0.694    1.3549E-4


                	oxygen: data discarded
  252-253       	O022
  277-295       	O027
  312-325       	O023

                	sound speed:  no fit

  240-251       	V216
  254-276       	V216
  277-279       	V116
  
                	sound speed: data discarded
  252-253       	V216
  280-311       	V217
C.1.e	Calibration

All sensors were precalibrated at the calibration laboratory of IfMW.
Each oxygen sensor was recalibrated with water samples during the
cruise at the first station when it was taken.  The calibration
constants of all sensors were checked up by in situ comparisions of p,
T,C, O2.

C.1.f	CTD Errors and Noise

During the cruise located faulty sensors were replaced as listed above in the 
CTD sensor configuration list.  After the cruise following sensor failures were 
detected and the data were discarded:

Oxygen from station 277-434 Speed of sound from station 280-311

C.2	Water sampling for In Situ Comparisons

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 CTDO data.

C.3	Salinity

The water sample salinities were measured with a Guildline Autosal Model 8400A 
salinometer, manufactured by Guildline Instruments Ltd., Smiths Falls, Canada.  
The salinometer was standardized weekly with IAPSO Standard Seawater (SSW) Batch 
P 111.  Differences in standardization readings were less than 3.

The salinometer manufacturer claims a precision of 0.0002 and an accuracy of 
better than 0.003; better than 0.001 when the laboratory temperature is constant 
(=/- 1K) and about 1-2 K below the bath temperature of the salinometer.


C.4	 Oxygen

The dissoloved oxygen samples were analysed by the Winkler Titration Method  
modificated by CARRITT and CARPENTER (1966).

Temperature (reverse thermometers) The following reverse thermometers were used: 
manufactured by: VEB Thermometerwerk Geraberg,Germany 

                       scale          graduated in
--------------------------------------------------------------
 pressure protected  -2...+30degC      0.1K
 unprotected         -2...+30degC      0.1K
--------------------------------------------------------------

Duplicate Water Samples

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

            average difference  maximum diff. standard deviation
            between samples                   of all differences
----------------------------------------------------------------
 salinity      0.0015 PSU        0.009 PSU      0.0018
 oxygen        0.011  ml/l       0.03  ml/l     0.0189
----------------------------------------------------------------

C.5	 Laboratory and Sample Temperatures

The laboratory was temperature controlled :24...26 degC. The bath temperature of 
the Autosal salinometer was set to 27 degC. Salinity and oxygen samples had been 
tempered at room temperature when measured.


C.5.a  Standards used

I.A.P.S.O Standard Seawater ,Batch P111 , 7.2.89 During the cruise this batch 
was used only.

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.

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

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.

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 ebc2.sum,  
ebc2.hyd, ebc2.csl and *.wct files.  The ebc2.sum file contains a summary of the 
location, time, type of parameters sampled, and other pertient information 
regarding each hydrographic station.  The ebc2.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 ebc2.wct.zip. The ebc2.csl file is a listing of ctd 
and calculated values at standard levels.

**NOTE**  Preliminary *.csl files were not created due to the CTD data being 
provided with non-uniform levels. 

Cruise Plan

Line  AR6      Lisbon to Madeira to Morocco

Logistical requirements:
Length (nm): 1590
Small Volume Stations:   54
Repeats/Yr: 4x        No. of Yrs: 1
Program constraints: Vessel to be equipped with GPS and ADCP and done once in
                     each season with 30 nm station spacing. Accuracy
                     requirements spelled out by CP1-4.

     Operator: GERMANY
     Chief scientist: Hagen/IOW
     Ship: VON HUMBOLDT,           Cruise/leg: 07AL991/2
     Cruise date: Sept. 2-Sept. 1 1991
     Cruise plan received:   Sept. 90
     Cruise report received: Sept. 93
     ADCP: Mittelstaedt/BSH
     CTD: Hagen/IOW
     Meteorological measurements: Unknown
     Oxygen: Hagen/IOW
     Salinity: Hagen/IOW
     Thermosalinograph: Feistel/IOW
     Notes: Work also done in AR16 area.


     Operator: GERMANY
     Chief scientist: Hagen/IOW
     Ship: VON HUMBOLDT,           Cruise/leg: 07AL991/3
     Cruise date: Sept. 17-Oct. 1 1991
     Cruise plan received:   Sept. 90
     Cruise report received: Sept. 93
     ADCP: Mittelstaedt/BSH
     CTD: Hagen/IOW
     Meteorological measurements: Unknown
     Oxygen: Hagen/IOW
     Salinity: Hagen/IOW
     Thermosalinograph: Feistel/IOW
     Notes: Work also done in AR16 area.
