"Climate and Forecast (CF)" . . "downwelling shortwave flux in sea water" . . . " Downwelling radiation is radiation from above. It does not mean \"net downward\". 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. \"shortwave\" means shortwave radiation. " . .