NORMAL HEAT SOURCES AND SINKS IN THE LOWER TROPOSPHERE IN WINTER

Abstract

A synthesis is made of several published studies of the normal heat budget of the lower troposphere over the Northern Hemisphere in winter. Charts of heat sources and sinks are presented, based on two independent methods, one using the thermodynamic energy equation and the other a heat-balance procedure. Although there are differences in important details, both methods indicate that the horizontal scale of heating is the same as that of the normal lower-tropospheric temperature field, but that the field of heating is almost 90° out of phase with that of temperature. This result has an important bearing on the energy budget of the circulation. It is concluded that the heat-balance method is correct in indicating that there is a positive correlation between the normal temperature and heating fields. According to the energy transformation equations, this means that there is a positive transformation from heating to potential energy at the scale of the climatological long waves. This energy is directly available for maintaining these waves against friction. It is hoped that this study will be of some use in the design of numerical general circulation experiments, and as a basis of comparison with data from meteorological satellites.