A Study of Mesoscale Atmospheric Circulations Induced by Land Surface Heterogeneity

Mesoscale circulations induced by complex land surface have been investigated using linear stochastic models and a nonlinear numerical model. Random distributions of differential surface heating and variable topography are described in terms of homogeneous random fields. Analytical solutions for the linear atmospheric systems under these random surface forcings have been obtained. The stochastic linear theory suggests that thermally induced flow is strongly inhibited in an environment of stable stratification and moderate synoptic wind. Numerical experiments indicate that mesoscale momentum fluxes are more important than turbulent fluxes and mesoscale heat fluxes are not significant in the thermally induced flow. The stochastic linear theory also shows that mountain waves over random topography are effective in inducing momentum fluxes, but not effective in inducing heat fluxes. Thesis Supervisor: Rafael L. Bras Title: Bacardi and Stockholm Water Foundations Professor Thesis Co-Supervisor: Elfatih A. B. Eltahir Title: Assistant Professor