Climate and Forecast Standard Names
diffuse_downwelling_shortwave_flux_in_air
'Diffuse' radiation is radiation that has been scattered by gas molecules in the atmosphere and by particles such as cloud droplets and aerosols. Downwelling radiation is radiation from above. It does not mean 'net downward'. The sign convention is that 'upwelling' is positive upwards and 'downwelling' is positive downwards. The term 'shortwave' means shortwave radiation. 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.