HR: 1330h
AN: A42B-0764    [PDF]
TI: Estimates of the Atmospheric Water Balance Over the Oceans
AU: Gruber, A
EM: Arnold.Gruber@noaa.gov
AF: NOAA/NESDIS Cooperative Institute for Cliamte Studies, Earth System Science Interdisciplinary Center 2207 Computer and Space Sciences Building, Room 4115D, College Park, MD 20742-2465 United States
AU: * Salapata, D J
EM: salapata@essic.umd.edu
AF: ESSIC/CICS, Earth System Science Interdisciplinary Center 2207 Computer and Space Sciences Building, Room 4115F, College Park, MD 20742-2465 United States
AB: With the availability of global re-analysis and global satellite observations, the study of the global water balance has received renewed interest. In this study, we have focused on calculating flux divergence and residual evaporation rates over the oceans using observed data sets where available. To calculate these terms, we are using 6-hourly global winds and pressure fields from NCEP/DOE Reanalysis II, moisture fields from NVAP (National Aeronautical and Space Administration Water Vapor Project), a satellite and in situ water vapor set, and precipitation from GPCP (Global Precipitation Climatology Project) and CMAP (Climate Prediction Center Merged Analysis of Precipitation), both a satellite and in situ precipitation data set. All data sets are from the time period 1988-1992 and the height dependent variables are vertically integrated for the first 18 sigma levels representing pressure levels over the oceans from the surface to approximately 200 mb. These data sets were used in various combinations to compute flux divergence, which is essentially equal to evaporation minus precipitation (E-P) since the storage term is small, and evaporation as a residual using the GPCP and CMAP precipitation data. We also calculated the water balance from the NCEP/DOE re-analysis for comparison. The evaporation minus precipitation fields are compared to other independent calculations, such as HOAPS (Hamburg Ocean-Atmosphere Parameters and Fluxes from Satellite Data), NODC (National Oceanographic Data Center), and SOC (Southampton Oceanographic Centre). Comparisons to these data sets show that our method produces similar patterns as those of the other data sets. The main differences are in the magnitude of the flux values and some regions of maxima and minima, but none of the four results agree completely in that regard. The evaporation was calculated as a residual by taking the flux divergence values and adding precipitation estimates to obtain evaporation values. Evaporation calculations were made using various combinations of input data; 1) NVAP water vapor, GPCP precipitation, and NCEP re-analysis II wind, 2) NVAP water vapor, CMAP precipitation, Re-analysis II winds, and 3) Re-analysis II water vapor, precipitation, and winds. These were compared to independent evaporation estimates from SOC, NODC, HOAPS, and Reanalysis II, and the results were evaluated.
DE: 0312 Air/sea constituent fluxes (3339, 4504)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 4504 Air/sea interactions (0312)
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting