############################################################################## # ############################################################################## # ISLSCP II Air-Sea Carbon Dioxide Gas Exchange # ############################################################################## The files in this directory were produced by the Takahashi CO2 Group of Lamont- Doherty Earth Observatory at Columbia University. Any problems encountered with the data set should be reported to Eric Brown de Colstoun at ericbdc@ltpmail.gsfc.nasa.gov or David Landis at David.R.Landis@gsfc.nasa.gov ############################################################################## There are eight files in this data set. File Naming Convention -------------------- The following files are included in this data set: air_sea_d-pco2_5d_1995.csv: Original data file submitted by the Principal Investigator in comma-delimited format. This original data file contains monthly CO2 partial pressure difference (delta-pCO2) in seawater corrected to 1995 with ancillary data, and interpolated onto a 5-degree longitude by 4-degree latitude Earth grid. These data are used to calculate the ocean/air CO2 flux. air_sea_d-pco2_5d_1995.zip: A point shape file of the lat/lon data from the file above. This file includes six files: air_sea_d-pco2_5d_1995..xxx where xxx is .dbf, .prj, .sbn, .sbx, .shp, and .shx. air_sea_d-pco2_5d_1995_12month.zip: A polygon shape file of 12 months of data from the 12 files in air_sea_d-pco2_5d_1995.csv. This also includes seven files: air_sea_d-pco2_5d_1995_12month.xxx where xxx is .dbf, .prj, .sbn, .sbx, .shx.,.shp., and .xml. air_sea_co2flux_5d_1995.csv: Original data file submitted by the Principal Investigator in comma-delimited format. This original data file contains monthly global ocean/air CO2 fluxes for 1995 with ancillary data, as output from the Takahashi interpolation scheme. These files are also interpolated onto a 5-degree longitude by 4-degree latitude Earth grid. air_sea_co2flux_5d_1995.zip: A point shape file of the lat/lon data from the file above. This file includes six files: air_sea_co2flux_5d_1995.xxx where xxx is .dbf, .prj, .sbn, .sbx, .shp, and .shx. air_sea_co2flux_5d_1995_12month.zip: A polygon shape file of 12 months of data from the 12 files in air_sea_co2flux_5d_1995.csv. This also includes seven files air_sea_co2flux_5d_1995_12month.xxx where xxx is .dbf, .prj, .sbn, .sbx, .shx.,.shp and.xml. 1-degree files: File: air_sea_co2fluxmaps_1d.zip: Contains 12 files (.asc) of monthly average ocean/air CO2 flux data named air_sea_co2flux_1d_1995MM00.asc. where MM is the month from 01 to 12. The 00 means this is a monthly average. File: air_sea_d-pco2_maps_1d.zip: Contains 12 files (.asc) of monthly average seawater-air pCO2 difference data, named air_sea_d-pco2_1d_1995MM00.asc where MM is the month from 01 to 12. The 00 means this is a monthly average. File descriptions: Original Data Files (Both files have 21,109 total rows) air_sea_d-pco2_5d_1995.csv has a total of 9 columns.Both files have 21,109 total rows. The contents for each column of the "air_sea_d-pco2_5d_1995.csv" file are given below. This file contains monthly pCO2 in seawater data corrected to 1995, and interpolated onto a 4-degree latitude by 5-degree longitude grid. - LON and LAT refer to longitude and latitude, respectively. Latitude convention is North latitude is positive, South latitude is negative. Negative longitudes are W and positive longitudes are E. Latitude and Longitude refer to the coordinate of the center of the grid cell, in decimal degrees. - SST is sea surface temperature, in degrees C, interpolated onto the same 4- degree by 5-degree grid. The source is monthly data on a 1-degree by 1-degree grid from NODC World Ocean Database 1998. - SAL is salinity (unitless), from the same source as SST. - BARO is monthly climatological mean barometric pressure in millibars interpolated onto our 4-degree by 5-degree grid, from a 2-degree by 2-degree monthly data base from NCAR. - PCO2_SW is monthly pCO2 (uatm) in surface water at SST (For a reference year 1995, 4-degree latitude by 5-degree longitude pixels.) - PCO2_AIR is monthly pCO2 (uatm) in air for 1995 (Computed using: (a) the zonal mean CO2 conc. in dry air from Global View for 1995, (b) climatological monthly mean barometric pressure in 2 by 2 degree pixels from NCAR, (c) SST referenced above and, (d) salinity referenced above.) - DELTA_PCO2 is seawater - air pCO2 difference (uatm) (For a reference year 1995 computed using PCO2_SW, and PCO2_AIR data cited above). The contents for each column of the "air_sea_co2flux_5d_1995.csv" file are given below. This file contains the output of the Takahashi interpolation scheme for estimating global ocean/air CO2 flux. This is the "940K" version and uses the DELTA_PCO2 data generated above. In this file a value of -888.8 indicates the presence of sea ice which inhibits sea-air gas exchange. - LON, LAT are as above. - DELTA_PCO2 is monthly pCO2 (uatm) in air for 1995 as above. - WIND_SPD is the wind speed in m/sec. - SST is sea surface temperature as above. - CO2_FLUX is the monthly ocean/air CO2 flux in moleC/m2. Negative fluxes are into the oceans while positive fluxes are from the ocean to the air. Mapped Files: air_sea_co2fluxmaps_1d.zip air_sea_d-pco2_maps_1d.zip These files are at a resolution of 1 x 1-degree and thus have 360 columns by 180 rows. All values in these files are written as real numbers. These maps were created from the original 5 x 4-degree data files, and the original missing values of -999.9 are preserved. Additionally, the ISLSCP II 1-degree Land/Sea Mask was overlaid on the files, inserting the land (listed as -99.9) at a finer scale than the original 5 x 4-degree data. Thus, there is missing land data listed as -99.9, then additional missing data listed as -999.9. Sea ice is indicated by -888.8 in the CO2 flux files. These files are all gridded to a common equal-angle lat/long grid, where the coordinates of the upper left corner of the files are located at 180 degrees W, 90 degrees N and the lower right corner coordinates are located at 180 degrees E, 90 degrees S. Data in the files are ordered from North to South and from West to East beginning at 180 degrees West and 90 degrees North. WARNING: The 1 x 1-degree map product is for browse use only. These data files were created from the original 5 x 4-degree data, and are not interpolated between the original 5 x 4 pixels. Use these data with caution and always refer to the original tabular data files for specific information. ##############################################################################