A GENERALIZATION OF GILLS HEAT-INDUCED TROPICAL CIRCULATION

In this note, the local solution of Gill for the symmetric and the ant isymmetric heat sources and sinks is extended to the entire global tro pical belt by the authors. The symmetric and antisymmetric heating for ced solutions of the motion field derived from the linearized shallow- water equations describe many aspects of the winter and the summer mon soon circulations. The extension, provided here, describes the respons e of tropical circulation to the global tropical heat sources and sink s retrieved from a satellite-based field of the outgoing longwave radi ation through regression algorithms. Such a prescribed field is expand ed into a low-order set of trigonometric functions in the zonal direct ion and parabolic cylinder functions along the meridional coordinate. Upon sequential substitution of these modes into the linearized shallo w-water equations on a beta plane, it is possible to solve for the hea ting forced solutions in a closed analytical form for the entire Tropi cs. The solutions exhibit most of the climatological features of the w intertime and the summertime circulations of the lower troposphere, su ch as the trades of the two hemispheres and the Asian monsoon with its elements; for example, monsoon trough, cross-equatorial hows, southwe st monsoon current, Mascarene high, and the subtropical anticyclones. Furthermore, the solutions also describe features such as the heat low s over Arabia, the Sahara, and Mexico. Overall, these solutions confir m the importance of diabatic heat sources and sinks:in the shaping of the tropical climate.