Solar radiation enters the Earth's atmosphere with a portion being scattered by clouds and aerosols.

Processing, archiving and distributing Earth science data
at the NASA Langley Research Center

What are TOA and Surface Fluxes?

The-Top-of-Atmosphere (TOA) layers are where the first interaction occurs as the radiation from the Sun reaches Earth and then the various atmospheric layers containing gases, clouds, aerosols, and/or other constituents before finally reaching the Surface. Solar radiation is scattered and/or absorbed in each of these material layers while the atmospheric and surface constituents emit their own share of radiation. Shortwave (SW) and Longwave (LW) are the two primary spectral parts the energetics can be split into and may be further divided into finer spectral intervals depending on the specifics of the physical processes under investigation.