Interrelationships between atmospheric turbidity, the diffusely reflected visible radiation at the top of the earth's atmosphere and the global solar radiation at the surface

Abstract

The flux of radiation emerging at the top and bottom of a realistic model of a cloud-free, plane-parallel, vertically inhomogeneous turbid atmosphere has been computed for different values of atmospheric turbidity and surface albedo in 83 unequal spectral intervals over the short-wave or solar radiation (0.285–2.5 μm) regime. These computations have been utilized to determine the diffusely reflected radiation at the top of the atmosphere in the spectral interval 0.535–0.7035 μm (which covers the visible channels of the radiometers onboard the Geosynchronous Operational Environmental Satellites and the NOAA polar orbiting satellites) and in the spectral interval 0.375–0.7035 μm. The total global solar radiation (0.285–2.5 μm) reaching the surface has also been determined. Simple linear regression relationships have been established between (i) the reflected radiation at the top and atmospheric turbidity and (ii) between the global radiation at the surface and the reflected radiation at the top. These regression relationships yield coefficients of determination very close to unity. The implications of this strong linear dependence of the reflected radiation on atmospheric turbidity and of the global radiation at the surface on the reflected radiation at the top to satellite-based studies of the feasibility of estimation of the insolation (global radiation) at the surface are briefly mentioned.