A Numerical Case Study of the Effects of Latent Heating on a Developing Wave Cyclone

Abstract

The effects of latent heating on the development of a wave cyclone are investigated using a multi-level primitive equation model to simulate the cyclone system with (wet) and without (dry) latent heating. While the dry simulation failed to properly predict either the formation of the closed circulation which developed throughout the depth of the troposphere or the pronounced northwest-to-southeast horizontal tilt of the upper-level trough shown by observations, the wet simulation successfully reproduced both these features. The mechanisms for the generation of the regional-scale closed system are examined and the influence of latent heating on large-scale dynamics and energetics is discussed. Results indicate that latent heat release stabilized the troposphere and reduced the large-scale horizontal temperature gradient. Also, through the enhancement of ageostrophic flow, the addition of latent heat generated kinetic energy in both the lower and upper troposphere at the expense of the available potential energy.