9.8 Seabreeze Circulations and Offshore Waves Induced by Heating over High Coastal Topography

Wednesday, 1 September 2010: 9:30 AM
Alpine Ballroom A (Resort at Squaw Creek)
Qingfang Jiang, UCAR Project Scientist, NRL, Monterey, CA; and J. Doyle

Heating over the Andes has been identified as the primary source for temporal variations in low-level clouds and surface wind divergence offshore of the Chilean coast. In this analytical study, the characteristics and dynamics of offshore propagating waves and circulations induced by heating over coastal terrain are investigated using a multiple-layer linear model. The troposphere is represented by three discrete layers: a shallow viscous marine boundary layer underneath an inversion, a lower tropospheric layer and an upper tropospheric layer. Each layer is described by a uniform ambient wind vector (Ui, Vi), a constant buoyancy frequency, Ni, and a Rayleigh damping coefficient alpha_i. The heating anomaly over coastal topography is represented by a three-dimensional periodic heating function. The ambient wind and stability profiles and heating functions are approximated from observations and numerical model simulations over the Andes and the Southeast Pacific. A range of parameter space has been explored, with emphasis on the impact of the depth of the heating function, the vertical wind shear, boundary layer top inversion, and turbulence viscosity on offshore waves and near-shore circulations.
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