TITLE OF THE DATA SET Atmospheric CO2 concentrations derived from flask samples collected at U.S.S.R.-operated sampling sites. CONTRIBUTORS A. M. Brounshtein E. V. Faber A. A. Shashkov Main Geophysical Observatory Hydrometeorological Service of the U.S.S.R. Karbyshev Str 7 194018 St. Petersburg, U.S.S.R. SOURCE AND SCOPE OF THE DATA Daily atmospheric CO2 concentrations from four U.S.S.R.-operated sampling sites (Teriberka Station, Ocean Station Charlie, Bering Island, and Kotelny Island) are provided. The period of record varies by station with the earliest measurements dating back to 1983 and recent estimates from early 1991. These CO2 concentrations are derived from air samples collected in 1.5-L stainless steel electropolished flasks and later analyzed at the Main Geophysical Observatory (St. Petersburg, U.S.S.R.) using a nondispersive infrared gas analyzer. Measurements not meeting wind direction, wind speed, inter-flask agreement, and climate condition criteria have been either discarded or flagged. All measurements have been corrected for drift biases introduced during flask storage. These atmospheric CO2 concentrations are considered indicative of regional background air conditions and are directly traceable to World Meteorological Organization primary CO2 standards. DATA FORMAT Seven files are provided in this subdirectory including this documentation file (NDP033.TXT), four data files containing atmospheric CO2 concentrations from each of the four Soviet stations (KOTELNY.DAT, TERIBERK.DAT, STATIONC.DAT, & BERING.DAT), and a FORTRAN IV and SAS retrieval code to read and print the data files (NDP033.FOR & NDP033.SAS). The data files are each formatted as INTEGER SAMPYR, SAMPMO, SAMPDA, DAYYR REAL TIME, CONC, DIFF CHARACTER FLAG READ(5,100,END=99) SAMPYR,SAMPMO,SAMPDA,DAYYR,TIME, 1 CONC,DIFF,FLAG 100 FORMAT(5X,3(I2,1X),I3,1X,F8.4,1X,F8.4,1X,F5.1,3X,A1) where SAMPYR is the year the flask sample was collected; SAMPMO is the month the flask sample was collected; SAMPDA is the day of the month the flask sample was collected; DAYYR is the day of the year the flask sample was collected; TIME is the year and fraction of year expressed as a single decimal value; CONC is the average CO2 concentration (ppmv). If DIFF is > 1 ppmv, the lesser of the flask pair is chosen provided it is within 2 standard deviations of the plotted smooth curve. If one of the two samples is lost the same criteria is applied to the remaining sample concentration value. If DIFF is <1 ppmv, the mean of the flask pair is used. DIFF is the absolute value of the difference (ppmv) between the flask pair concentrations; FLAG is a flag describing the nature of DIFF. It is assigned a '+' if DIFF is less t or equal to 1, an 'S' if DIFF is greater than 1, and an 'M' if CONC is derived from a single flask. Missing values for the variable DIFF are represented by ~99.9. All the data (CONC) presented here have been adjusted for potential drifts in CO2 concentrations due to lengthy storage in stainle steel flasks. These adjustments have been made using the formula: dC = -t(0.23*e - 0.51) where dC is the correction added to the measured concentration value, t is the time in days between air sample collection and analysis, and e is the water vapor partial pressure in the air sample expressed in millibars. Stated in tabular form, the contents include the following. Variable Variable Starting Ending Variable type width column column SAMPYR Numeric I2 6 7 SAMPMO Numeric I2 9 10 SAMPDA Numeric I2 12 13 DAYYR Numeric I3 15 17 TIME Numeric F8.4 19 26 CONC Numeric F8.4 28 35 DIFF Numeric F5.1 37 41 FLAG Character A1 45 45 REFERENCES Brounshtein, A. M., N. N. Paramonova, A. D. Frolov, and A. A. Shashkov. 1976. Optical method for determination of CO2 total abundance in a vertical column of the atmosphere. Trudy GGO 369:5-25. Brounshtein, A. M., K. V. Kazakova, E. V. Faber, and A. A. Shashkov. 1988a. Measurements of the CO2 concentration vertical distribution above the continental regions. Annals of the MG 519:34-42. Brounshtein, A. M., E. V. Faber, and A. A. Shashkov. 1988b. Measurements of the CO2 concentration above Leningrad. Annals of the MGO 519:43-45. Brounshtein, A. M., K. V. Kazakova, V. I. Medinez, and E. V. Faber. 1988c. Measurements of the CO2 concentrations at Ocean Station "C" (North Atlantic). Annals of the MGO 519:27-43. Conway, T. J., P. 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