The Clouds and the Earth's Radiant Energy System (CERES) is a series of broadband scanning radiometers on board the TRMM, EOS/Terra, and future EOS/Aqua satellites. Beyond measuring the radiative fluxes at the Top Of the Atmosphere (TOA) CERES calculates, using a fast radiation transfer model along with a wide array of ancillary input data, a radiative flux profile through the atmospheric column. In order to validate these radiation transfer calculations the CERES/ARM Validation Experiment (CAVE) creates a database of temporally and spatially collocated surface radiation and broadband TOA satellite observations. Surface radiation measurements contained in the data base include all Atmospheric Radiatiom Measurement (ARM) sites, NOAA Surface Radiation (SURFRAD), Climate Monitoring Diagnostics Laboratory (CMDL), Baseline Surface Radiation Network (BSRN) and several "independent sites". A time history of the surface radiation (and other available data from the surface sites) has been placed into monthly files with a temporal resolution of 1/2 hour. Separate files, though written in similar format, contain CERES/TRMM and CERES/TERRA data that has been subset from the CERES ES8 (ERBE-Like) files. These instantaneous observations are placed into 1/2 hour bins matching in time the surface observations for ease of comparison.

When additional surface observations are available, such as surface meteorology, aerosol optical depth, and cloud observations, these data are also placed into the surface observation files. In some limited cases, atmospheric profiles of height, temperature, and water vapor are made available.

By using satellite and ground based cloud estimates for determining clear sky observations we calculate atmospheric absorption and cloud forcing. It is found that the ground based estimates of cloud amount (from the Long/Ackerman pyranometer method) are more sensitive to cloud than the CERES ES8 maximum likelyhood estimator method so to match the surface observations with the TOA one must relax the amount of cloud allowed into the "clear" absorption calculations.

All data can be accessed via the World Wide Web through the web site:

http://www-cave.larc.nasa.gov/cave

There, one can find explanations of the data files as well as graphical routines that can access the data base to supply summaries of the surface data, CERES data, and cloud information available.