Numerical simulation of cold surges.

Abstract

A global, six-level primitive equation model was numerically integrated to examine the interaction of a planetary wave with a growing mid-latitude baroclinic wave. The purpose of this study was to determine the contribution of the baroclinic wave to the initiation of a monsoon surge. Three experiments were run. Experiment I depicted the effect of the planetary wave on the southward migration of cold air. The cyclogenesis of a mid-latitude baroclinic wave was shown in Experiment II. Experiment III combined the growing baroclinic wave with the stable planetary wave in an attempt to simulate a cold surge. Characteristics of a monsoon surge were present in the numerical simulation but not to the extent or detail of observed surges . The results indicated the important role of planetary wave advections in the formation of cold surges.