THE SCALE OF NON-ADIABATIC HEATING AS A FACTOR IN CYCLOGENESIS

Abstract

With the aid of a simple linearized model, the effect of large-scale atmospheric heat sources on a resting atmosphere has been investigated. Particular emphasis has been devoted to the study of the dependence of pressure change on the horizontal dimension of the heat sources. It is thus found that, when the maximum intensity in the center of the heat source is independent of the horizontal dimension, the pressure fall at the surface has a maximum when the width is about 4000 km in the case of no friction. With friction included, the pressure change also depends on the rate of heating. With decreasing rate of heating, the pressure fall at the surface thus decreases while the width for which the maximum occurs increases (4000 to 5000 km). The mean wind decreases monotonically with increasing width of the heat source except for the very smallest scales. In the case where the maximum intensity in the center of the heat source is proportional to the horizontal extent, the pressure fall at the surface increases monotonically with increasing dimensions. The dependence on the latitude and the stability is investigated.