A validation of residual energy budgets from atmospheric circulation data against satellite measurements of the net radiation

The distributions of the net sources of atmospheric dry and latent energy are evaluated by the residual technique, using the re-analyzed ECMWF FGGE level IIIb data for February and July 1979. Their sum (i.e., the estimated source of total energy) is compared to simultaneous Nimbus 7 ERB estimates of the radiation balance at the top of the atmosphere. Formally the difference between the two equals the net heat flux through the earth's surface. Over land the estimated total energy source should be nearly equal to the radiation balance. The best agreement is found in July 1979 over the northern hemisphere middle latitudes, where monthly averages over large land-areas agree to within 10 W/m2. In February, the residual is systematically too large by 20-40 W/m2 over the same regions. Elsewhere, differences of up to 60 W/m2 occur for corresponding averages. Over low latitude continents, the residuals are generally too small over convectively active regions and too large over subsidence regions. Over the oceans the difference between the net radiation and the total energy source compares favourably with available estimates of the climatological heat flux through the surface. The same is true for the residual source of latent energy and the fresh water flux through the surface