Sign conventions NCEP Reanalyses Fluxes

Radiative Fluxes

Where the direction of the radiative flux is included, the convention is that the flux is always positive because it is defined that way.
  • Downward longwave: always positive
  • Upward longwave: always positive
  • Downward shortwave: positive or zero (never negative)
  • Upward shortwave: positive or zero (never negative)