=============================================================================== OAFLUX MONTHLY DATA DESCRIPTION =============================================================================== ***** Last updated on 5/31/2011 ***** The latent heat flux, sensible heat flux, evaporation, and flux related surface meteorological variables have been updated to 4/30/2011. The files of 2011, which were identified by "nrt", are the interim products. October 2009 The latent heat flux, sensible heat flux, evaporation, and flux related surface meteorological variables have been updated to 12/31/2008. The surface radiation fluxes, which are taken from ISCCP, have been updated to 12/31/2007. In addition to the extension of time-series, the analysis of air temperature has been reprocessed for the period from 09/01/2002 to 12/31/2006 as the ERA-interim was used to replace the NCEP/NCAR Reanalysis after the end of ERA40 to prevent the Gibbs-like phenomena caused by the NCEP/NCAR Reanalysis product over ocean near steep orography. The associated latent and sensible heat fluxes, as well as evaporation, have also been updated since 09/01/2002. January 2008 The Objectively Analyzed Air-sea Fluxes (OAFlux) project at the Woods Hole Oceanographic Institution (WHOI) released in January 2008 a multidecade, global analysis for latent and sensible heat fluxes, ocean evaporation, and flux-related surface meteorological variables. Monthly, 1-degree gridded products are available online for the period 1958-2006, and daily gridded products are released for the satellite era 1985-2006. The data after 2006 will be updated in due course. The OAFlux project is supported by the NOAA Office of Climate Observations (OCO). This is the third release of the OAFlux products (Yu et al. 2008). The first data release was made in March 2004 for air-sea fluxes in the Atlantic Ocean (1988- 1999) under the auspices of the NOAA CLIVAR-Atlantic program. The second release was for air-sea fluxes over the global oceans (1981-2002) supported by the NOAA Office of Climate Observations (OCO) and Climate Change and Data Detection (CCDD) programs. All data files are in netCDF format and are compressed. *** Please note *** The flux and basic meteorological variables were saved by using "ncshort" format to minimize the size of the file. Land and missing values are 32766. All flux variables are multiplied by a factor of 10, surface meterological variables by 100, and evaporation by 10. The monthly directory contains four subdirectories: (1) evaporation_1958-2006 The directory has monthly-mean ocean evaporation as well as monthly-mean error averaged over the daily estimates. The two sets of monthly estimates are grouped into one data file for each year. The yearly files are named as: evapr_oaflux_yyyy.nc.gz, where “yyyy” denotes the four-digit year. The unit is cm/year. (2) turbulence_1958-2006 The directory has monthly-mean global analysis of latent heat flux (lh_oaflux_yyyy.nc.gz, positive upward), sensible heat flux (sh_oaflux_yyyy_nc.gz, positive upward), the 10m neutral wind speed (ws_oaflux_yyyy.nc.gz), the 2m air humidity (qa_oaflux_yyyy.nc.gz), the 2m air temperature (ta_oaflux_yyyy.nc.gz), and sea surface temperature (ts_oaflux_yyyy.nc.gz). The yearly files for each variable include also the monthly-mean error estimates for the corresponding variable. Units: latent and sensible heat flux (W/m2) wind speed (m/s) specific humidity (g/kg) air and sea-surface temperatures (degree-C) (3) radiation_1983-2004 The surface radiation data in this directory are taken from the International Satellite Cloud Climatology Project (ISCCP; Zhang et al. 2004). The ISCCP-FD data are kindly provided by Dr. William B. Rossow for distribution along with the OAFlux products. Please reference the ISCCP webpage http://isccp.giss.nasa.gov/projects/flux.html about the project and the full global dataset. The ISCCP data hosted here include net longwave radiation (lw_isccp_yyyy.nc.gz, positive upward) and net shortwave radiation (sw_isccp_yyyy.nc.gz, positive downward) at the ocean surface. The data are available from 7/1/1983 to 12/31/2004 and came with no error analysis. The unit is W/m2. Please note that the original net longwave and shortwave radiations from ISCCP have a three-hour resolution and are on 2.5-degree grid over the globe. We applied daily average and linearly interpolation to the ISCCP dataset to produce the same spatial and temporal resolution as the OAFlux product. The monthly-mean fields were averaged from the daily fields. (4) netheat_1983-2004 The daily net heat flux (qnet_yyyy.nc.gz, positive downward) results from combining the OAFlux latent and sensible heat fluxes with the ISCCP ocean-surface radiation. The net heat flux, qnet, is computed as: qnet = SW- LW - LH - SH. The unit is W/m2. References: Yu, L., X. Jin, and R. A. Weller, 2008: Multidecade Global Flux Datasets from the Objectively Analyzed Air-sea Fluxes (OAFlux) Project: Latent and sensible heat fluxes, ocean evaporation, and related surface meteorological variables. Woods Hole Oceanographic Institution, OAFlux Project Technical Report. OA-2008-01, 64pp. Woods Hole. Massachusetts. Yu, L., and R. A. Weller, 2007: Objectively Analyzed air-sea heat Fluxes (OAFlux) for the global oceans. Bull. Ameri. Meteor. Soc., 88, 527-539. Yu, L., 2007. Global variations in oceanic evaporation (1958-2005): The role of the changing wind speed. J. Climate, 20(21), 5376-5390. Zhang, Y-C., W.B. Rossow, A.A. Lacis, V. Oinas, and M.I. Mishchenko, 2004. Calculation of radiative fluxes from the surface to top of atmosphere based on ISCCP and other global data sets: Refinements of the radiative transfer model and the input data. J. Geophys. Res., 109, D19105, doi:10.1029/2003JD004457. Created: January 2008 L. Yu