. "downwelling radiative flux in sea water" . . . "Climate and Forecast (CF)" . "Downwelling radiation is radiation from above. It does not mean \"net downward\". Radiative flux is the sum of shortwave and longwave radiative fluxes. When thought of as being incident on a surface, a radiative flux is sometimes called \"irradiance\". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called \"vector irradiance\". In accordance with common usage in geophysical disciplines, \"flux\" implies per unit area, called \"flux density\" in physics." . .