What are the definitions of the radiation fields?

• "Surface solar radiation downwards" (SSRD) is the incident solar (shortwave) radiation and "surface solar radiation" (SSR) is the net solar radiation (the fraction of solar radiation not reflected by the surface). "Surface net solar radiation, clear sky" (SSRC) is a hypothetical field of net solar radiation assuming no clouds.
• "Surface thermal radiation downwards" (STRD) is the incident thermal (longwave) radiation and "surface thermal radiation" (STR) is the net thermal radiation. "Surface net thermal radiation, clear sky" (STRC) is a hypothetical field of net thermal radiation assuming no clouds.
• "Top solar radiation" is the net solar (shortwave) radiation at the top of the atmosphere (TOA). "Top net solar radiation, clear sky" is a hypothetical field assuming no clouds.
• "Top thermal radiation" is the net thermal (longwave) radiation at the top of the atmosphere. "Top net thermal radiation, clear sky" is a hypothetical field assuming no clouds.

Additional details on radiation parameters can be found here: Radiation-quantities-ecmwf-model-and-mars.pdf (document correct as of Cycle 41R1).