Explanation of Columns for 1995 UW pCO2 Data Julian Date - Julian day. decimal day Date - month/day/year Time - Greenwich Mean Time; hour:minute:second Lat - Latitude; degrees.decimal degrees Long - Longitude; degrees.decimal degrees XCO2eq - xCO2 in equilibrator, see below (ppm) xCO2,w - xCO2 concentration in water (ppm) xCO2,a - xCO2 concentration in air (ppm) Eq Temp - Equilibrator temperature (oC) Pressure - Atmospheric pressure (mbars) SST(TSG) - Sea Surface Temperature from bow thermosalinograph (oC) Salinity (TSG) - Sea Surface Salinity from bow thermosalinograph (ppt) f(CO2)w, equil - CO2 fugacity of water in the equilibrator (ppm) f(CO2)w, in situ - CO2 fugacity of water in the surface water (ppm) f(CO2)a - CO2 fugacity of the marine boundary layer atmosphere (ppm) d_fCO2 - The flux of CO2 (ppm). (fCO2w, insitu - fCO2a). Calculations The dry mixing ratios of ambient air and equilibrated headspace air are calculated by fitting a second-order polynomial through the hourly averaged response of the detector versus mixing ratio of the standards. Mixing ratios of dried equilibrated headspace and air are converted to fugacity of CO2 in surface seawater and water saturated air in order to determine the delta(ƒCO2) which is (ƒCO2eq-ƒCO2a). For ambient air and equilibrator headspace the ƒCO2a, or ƒCO2 eq is calculated assuming 100 % water vapor content: fCO2a/eq = [XCO2a/eq (P-pH2O)]*exp(B11 + 2del(12))*P/RT(sst/eq) where fCO2a/eq is the fugacity in ambient air or equilibrator, pH2O is the water vapor pressure at sea surface temperature, P is the atmospheric pressure (in atm) , and T(sst/eq) is the sea surface temperature(sst) or equilibrator temperature (in K) and R is the ideal gas constant (82.057 cm3 atm/deg/mol). The exponential term is the fugacity correction where B11 is the second viral coefficient of pure CO2 (B11= -1636.75 + (12.0408*T) - (0.0327957*T*T) + 3.16528*10-5 T*T*T ) and (12=(57.7 - 0.118 T) is the correction for an air-CO2 mixture in units of cm3/mol (Weiss, 1974) . The calculation for the fugacity at SST incorporates a temperature correction term for the increase of ƒCO2 due to heating of the water from passing through the pump and through 100 meters of 5 cm inner diameter (ID) PVC insulated tubing within the ship. The water in the equilibrator is typically 0.2 degrees Celcius warmer than sea surface temperature. The empirical temperature correction from equilibrator temperature to SST is outlined in Weiss (1982): delta ln(fCO2) = (teq -SST) (0.0317-2.785ee-04 teq - 1.839ee-03 ln (fCO2eq) where delta ln(fCO2) is the difference between the natural logarithm of the fugacity at teq and SST, and teq is the equilibrator temperature in degrees Celcius. Itinerary MALCOLM BALDRIGE 1995 FIELD SEASON FORMAT: Cruise : Project : Date : Port of Call MB95-01 : Radiatively Important Trace Species (RITS) : Depart-2/13/95-Miami, FL : Arrive-2/17/95-San Juan, Puerto Rico MB95-01 Radiatively Important Trace Species (RITS) Depart-2/22/95-San Juan, Puerto Rico Arrive-3/17/95-Durban, South Africa MB95-02 World Ocean Circulation Experiment (WOCE) Depart-3/21/95-Durban, South Africa Arrive-4/20/95-Colombo, Sri Lanka MB95-03 Global Ocean Ecosystem and Coupling (GLOBEC) Depart-4/27/95-Colombo, Sri Lanka Arrive-5/25/95-Muscat, Oman MB95-04 World Ocean Circulation Experiment (WOCE) Depart-5/31/95-Muscat, Oman Arrive-6/23/96-Male, Maldives MB95-04 World Ocean Circulation Experiment (WOCE) Depart-6/24/95-Male, Maldives Arrive-6/30/95-Victoria, Seychelles MB95-05 World Ocean Circulation Experiment (WOCE) Depart-7/12/95-Victoria, Seychelles Arrive-7/24/95-Muscat, Oman MB95-06 Global Ocean Ecosystem and Coupling (GLOBEC) Depart-7/31/95-Muscat, Oman Arrive-8/28/95-Diego Garcia, UK MB95-07a Ocean-Atmosphere Carbon Exchange Study (OACES) Depart-8/30/95-Diego Garcia, UK Arrive-9/8/95-Fremantle, Australia MB95-07 Ocean-Atmosphere Carbon Exchange Study (OACES) Depart-9/22/95-Fremantle, Australia Arrive-10/25/95-Male, Maldives MB95-08a Tropical Ocean Global Atmosphere/ Tropical Atmosphere & Ocean (TOGA/TAO) Depart-10/28/95-Male, Maldives Arrive-11/8/95-Darwin, Australia MB95-08b Tropical Ocean Global Atmosphere/ Tropical Atmosphere & Ocean (TOGA/TAO) Depart-11/21/95-Darwin, Australia Arrive-12/15/95-Pago Pago, American Samoa MB95-08c Tropical Ocean Global Atmosphere/ Tropical Atmosphere & Ocean (TOGA/TAO) Depart-12/19/95-Pago Pago, American Samoa Arrive-1/15/96-Rodman, Panama (Pacific) MB95-08c Tropical Ocean Global Atmosphere/ Tropical Atmosphere & Ocean (TOGA/TAO) Depart-1/20/96-Colon, Panama via Panama Canal Arrive-1/23/96-Miami, FL MB95-08c Tropical Ocean Global Atmosphere/ Tropical Atmosphere & Ocean (TOGA/TAO) Depart-1/27/96-Miami, FL Arrive-1/29/96-Charleston, SC REFERENCES Chen H., Wanninkhof R., Feely R. A., and Greeley D. 1995. Measurement of fugacity of carbon dioxide in sub-surface water: an evaluation of a method based on infrared analysis. Technical Memorandum ERL-AOML 85, NOAA/AOML, Miami, FL, pp. 49. DOE. 1994. Handbook of methods for the analysis of the various parameters of the carbon dioxide system in sea water. Version 2. (A. Dickson and C. Goyet ed.) ORNL/CDIAC-74, 1991. Ho, D. T., R. Wanninkhof, J. Masters, R.A. Feely, C. Cosca, 1997. Measurements of Underway fCO2 in the Eastern Equatorial Pacific on NOAA ships MALCOLM BALDRIGE and DISCOVERER from February to September, 1994. NOAA Data Report ERL AOML-30, 52pp. LI-COR. 1990. LI-6262 CO2/H2O Analyzer Operating and Service Manual. 9003-59, LI-COR, Lincoln, NB. Wanninkhof R. and Thoning K. 1993. Measurement of fugacity of CO2 in surface water using continuous and discrete sampling methods. Mar. Chem. 44, 189-205. Weiss R. F. 1974. Carbon dioxide in water and seawater: the solubility of a non-ideal gas. Mar. Chem. 2, 203-215. Weiss R. F., Janke R. A., and Keeling C. D. 1982. Seasonal effects of temperature and salinity on the partial pressure of CO2 in seawater. Nature 300, 511-513. Update 12/98 I calculated xCO2w (the xCO2w in original files is actually xCO2eq) using the approach by Weiss et all: Æ(ln(XCO2(teq-sst)) = ((teq-sst)*(0.03107-0.00027851*teq- 0.0018391*ln(XCO2eq*0.000001))) The original column heading xCO2w is changed to xCO2eq and the new xCO2w, calculated per formula above, is added right next to it. xCO2 was only calculated for the instances that fCO2w was originally calculated. In addition all files were checked that if fCO2a or fCO2w had default values of -999.99 that the ÆfCO2 had -999.99 as well All files files were insprected as follows: Visual inspection: Plot of Long vs. Lat Plot of JD vs. fCO2eq and xCO2 Plot of JD vs. salinity Plot of JD vs. SST and Teq Plot of JD vs. P I spot-checked the calculation of fCO2w and fCO2a. The values were up to 0.3 uatm different from those I calculated by hand because: 1. The fCO2 air is calculated using the Pbaro at the time of measurement. This pressure is not recorded in the final file, instead the P during the water measurement is listed (taken up to 20 minutes earlier or later) 2. The different H20 vapor algorithm differs by about 1 mB at SST of 30 C 3. The H2O correction for fCO2eq is calculated at SST in the data reduction while my program calculates it at Teq (Note, since the water vapor correction is not applied going from fCO2eq to fCO2w the procedure used in the data reduction yields a slightly incorrect fCO2eq but a correct fCO2w) "GR AIR VS RUG MB-0X". Errors in original data files (these have been corrected in the new *.csv files): MB-06f JD 221.271 : xCO2 missing: should have default value of -999.99 MB-07f JD 302.223 wrong Lat and Long JD 302.74 wrong Lat and Long JD 302.771 wrong Lat and Long JD 303.261 wrong Lat and Long The Pacific sector: MB95-08b.rik and MB95-08c.rik were checked on 4/20/99. No column of XCO2w was added to these files. These files originated from the FTP site that had a date 12/97.