Interannual Variability on Global and Regional Scales From the GEWEX Surface Radiation Budget Project

The GEWEX SRB project provides estimates of longwave and shortwave radiation at the Earth's surface for the period 1983-near present. The product is provided globally on a one degree grid at temporal resolutions ranging from 3-hourly to monthly. Inputs include water vapor and meteorology from the Goddard Earth Observing System (GEOS-1 for SRB Release 2.1, 1983-1991, and GEOS-4 for SRB Release 2.5, 1992-near present), Total Ozone Mapping Spectrometer (TOMS) ozone, and International Satellite Cloud Climatology Project (ISCCP) cloud and radiance information. Here we analyze the interannual variability in the data set. We correlate cloud information with longwave and shortwave surface and top of atmosphere fluxes and note the effects of El Nino/La Nina events and the Mount Pinatubo eruption. We examine the variability in the time series for different spatial regimes, including global, land, ocean and tropics. We compare to the Earth Radiation Budget Experiment and the Clouds and the Earth's Radiant Energy System data over the time range where there is relevant overlap. We perform Empirical Orthogonal Function (EOF) analysis to determine the amount of variability explained by the seasonal cycle, semi-annual cycle, ENSO, and North Atlantic Oscillation modes.