UNDERWAY fCO2 DATA DOCUMENTATION SHEET

•	Investigator responsible for measurements

First name: 	Arne 
Last name: 	Körtzinger
Organization: 	Leibniz-Institut für Meereswissenschaften, Kiel
Address: 	Düsternbrooker Weg 20
City: 	Kiel
Zip: 	24105
Country: 	Germany
Ühone:	+49 431 600 4205
Fax:	+49 431 600 4202
E-mail:	akoertzinger@ifm-geomar.de

•	Method description

Design of equilibrator
Type: 		bubbler/thin-film combination
Size (approximate total volume in L): 	1
Water flow rate (in L/min): 		2
Headspace gas flow rate (in L/min)	0.8
Vented? (yes/no): 		yes

Method of CO2 measurement
Gaschromatography/infrared/other: 	infrared
On wet/dry gas: 		wet

Information about calibration gases used
Manufacturer:		Messer-Griesheim GmbH
Concentrations of the calibration gases used: 	0 ppmv, 340.7 ppmv, 389.9 ppmv
Accuracy of the calibration gases used	+/- 0.5 ppmv

•	Measurement cycle information

Calibration frequency:			approx. every 6 h
Measurement frequency for air measurements:		approx. every 70 min
Measurement frequency for water measurements:	1-2 min
Are measurements averaged before reporting? (yes/no):	yes
If so, how many points and over what time period:	10 data per 1-min interval or 20 data per 2-min interval

Describe the calibration of the various sensors used:
Temperature:	checked against calibrated Pt-100 reference thermometer	
Pressure:	factory calibrated 

bibliographic citations to publications describing the method:
Körtzinger, A., H. Thomas, B. Schneider, N. Gronau, L. Mintrop and J.C. Duinker, 1996. Mar. Chem. 52, 133-145.
•	Cruise information

Experiment/cruise/leg(s): 		Cruise no. 30, leg 2
Dates:		Oct. 12 – Nov. 10, 1994
Ports:		Hamburg – St. John’s, Newfoundland
Vessel name:		METEOR
Country/institution owning/operating vessel:	Federal Republic of Germany/
			Reedereigemeinschaft Forschungsschiffahrt
Depth of sea water intake (in m): 	Ship’s clean seawater supply system with seawater intake at bow (depth ~3 m) 
location of air intake:		"monkeys island" above air chemistry lab
			(20 m above sea level)

What corrections were made to the CO2 concentration data prior to reporting it:
1)	xCO2 corrected for pressure and temperature fluctuations during measurements
2)	xCO2 corrected for dilution and pressure broadening due to water vapor
3)	xCO2 averaged over 1 minute
4)	xCO2 converted to fCO2 at 100 % humidity using measured atmospheric pressure and saturation water vapor pressure at equilibration temperature (calculated after Weiss and Price (1980)); 
5)	fCO2 is corrected to in-situ temperature (after Takahashi et al. (1993)

What corrections were made to the temperature data before reporting it: 	
	none

What corrections were made to the pressure data before reporting it:	
	none

Estimate overall precision and probable accuracy of the underway CO2 concentration measurements reported (for air and water separately): 	
	Water: ± 0.5 µatm; ± 2 µatm
	Air: ± 0.5 ppm;/ ± 1 ppmv

Estimate the precision and probable accuracy of the sea surface temperature measurements:
	0.01 °C; 0.05 °C

This data set should be cited as:
Körtzinger, A. (1993). Underway fCO2 measurements in the North Atlantic Ocean during the Meteor Cruise 30/2 in Oct./Nov. 1993.