Parameterization of Broadband Solar Radiation Transfer in Clear and Cloudy Atmospheres.

摘要

This report describes a parameterization model for computing solar heating rate and net flux profiles in clear and cloudy atmospheres. Specifically, the model is designed to allow global circulation and climate modelers maximum flexibility when treating the effects of clouds on the atmosphere. Gaseous water vapor, ozone and carbon dioxide are the absorbers considered in the clear atmosphere. The effect of Rayleigh scatter on net flux profiles is also discussed. The parameterization method is compared with results obtained by the discrete ordinate method and the comparisons for heating rate and net flux profiles are excellent for all solar zenith angles and surface albedos in the range 0.0-1.0. Reflection and transmission for cumulus, altostratus, cirrus and stratus are parameterized to allow variations in solar zenith angle, cloud thickness, and mean cloud temperature. The latter dependence means the cloud base becomes an independent variable.