On the Inclusion of Long-Wave Radiation in a Tropospheric Numerical Prediction Model

摘要

A simple method of computing long-wave radiative cooling in the troposphere associated with water vapor is described. Radiation from ozone and carbon dioxide is not considered. However, influences of arbitrary vertical distributions of cloud and moisture are included. Average annual cooling rates along a meridional cross-section are calculated for a cloudless atmosphere. The results agree fairly well with the total radiative cooling (long- and short-wave) as given by Manabe and Moller (1961) except in the lower troposphere at low latitudes. Here short-wave absorption by water vapor is appreciable. Long-wave radiative cooling is also computed in a case of a developing cyclone for comparison with release of latent heat. The largest cooling occurs at cloud top and can be a significant fraction of the amount of energy released as latent heat in the upper troposphere. Destabilization of the cloud mass and subsequent increase in precipitation may be important in cyclone development. (Author)