READCO2:
This README files accompanies the UWpCO2.csv file.  The UWpCO2.csv  file is a comma delimited ASCII file.   The data in this file were obtained from an underway pCO2 system which measured  bow ambient air and water partial pressures of CO2 (pCO2) quasi-continuously along the cruise track.  The water was obtained from a bow pump with an intake located 5 m below the water line.  The water flowed into a showed head equilibrator at a rate of 10-12 l/min where the headspace and water reached equilibrium with respect to pCO2.  Eighth equilibrator headspace (="water") samples and three air samples were obtained per hour. The average air values are merged with the water values for the particular hour to calculate the air -water fugacity difference.  The final values are expressed as fugacity which is the partial pressure corrected for the non-ideality of CO2 gas (Note: the fugacity is about (0.996* partial pressure)).

Column headings for  UWpCO2.csv: (Cells with missing values have a default of -999.99 assigned to them)

JD: fractional julian day (note, 1996 is a leap year)
Date: date
Time: time (GMT)
Lat: decimal latitude
Long: decimal longitude
xCO2,w: mixing ratio (= mole fraction) of dried headspace of the equilibrator [in ppm]
xCO2,a: mixing ratio (= mole fraction) of dried ambient bow air [in ppm]
Eq Temp: temperature in equilibrator (measured with a calibrated thermistor) [in degree centigrade)
Pressure: ambient pressure in the laboratory [in millibar)]
SST (TSG): sea surface temperature obtained from the thermosalinograph at the bow intake
Sal (TSG): salinity obtained from the thermosalinograph at the bow intake
f(CO2)w, equil: calculated fugacity for water saturated air in equilibrator [ in micro atm.]
f(CO2)w, in situ: calculated fugacity for water saturated air in the surface seawater [ in micro atm.]
f(CO2)a: calculated fugacity in bow air [ in micro atm.](note: due to frequent maneuvering, some of the values might be contaminated by stack gases.  Also, the values are up to 10 micro atm higher than remote oceanic values because of continental air influence.
DfCO2: f(CO2)w-f(CO2)a,  water-air fugacity (partial pressure) difference. Negative values indicate that the ocean takes up CO2.