"The surface called \"surface\" means the lower boundary of the atmosphere. \"Water\" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean \"net downward\". Spherical irradiance is the radiation incident on unit area of a hemispherical (or \"2-pi\") collector. It is sometimes called \"scalar irradiance\". The direction (up/downwelling) is specified. Radiation incident on a 4-pi collector has standard names of \"omnidirectional spherical irradiance\"." . "surface downwelling spherical irradiance in sea water" . . "Climate and Forecast (CF)" . . . .