INFLUENCE OF CLOUDS ON TRANSMITTED SOLAR RADIATION ABOVE AN INHOMOGENEOUS GROUND SURFACE

Monte-Carlo method has been applied to investigate the radiance and radiative flux on the horizontally inhomogeneous ground surface in a cloudy atmosphere.It has been found that the characteristics of the ground radiance and flux are significantly changed by clouds.The flux in the quadrant toward the surface with higher reflectivity are greater than that toward the surface with lower reflectivity.And the flux varies across the boundary of the two areas with different surface albedos.The effect of inhomogeneity of the surface albedo in a cloudy atmosphere can extend far to 20 km.In addition,the horizontal distribution of the flux absorbed by the ground is more homogeneous in a cloudy atmosphere than that in a clear air.