THE DISTRIBUTION OF RADIATIONAL TEMPERATURE CHANGE IN THE NORTHERN HEMISPHERE DURING MARCH

Abstract

The average radiation flux and flux divergence in the atmosphere during March is computed as a function of the chief absorbents of terrestrial and solar radiation, and the physical parameters of the atmosphere such as pressure, temperature and cloudiness. The infra-red flux for water vapor is computed graphically from Elsasser radiation charts. The absorption of insolation by water vapor is computed with the aid of an empirical formula. The net radiation-flux divergence is then computed by methods of finite differences. It is shown that the entire troposphere constitutes an energy source as far as radiative processes are concerned, and that at all latitudes the largest radiational heat loss is in the middle troposphere. It is also shown that the effect of cloudiness is to concentrate this maximum radiational cooling to layers at about the height of middle cloudiness (3–4 km). The net heat loss at this level is found to be about 1.5–2.0 C/day. It is suggested that the major contribution to heating the troposphere, to offset the loss due to radiation, is the release of latent heat by condensation.