Extended Abstract (220K)6.4
A linear theory of orographic precipitation
Ronald B. Smith, Yale University, New Haven, CT; and I. Barstad
A linear model of orographic precipitation is developed, including airflow dynamics, condensed water advection and downslope evaporation. The formulation extends the widely used upslope model and the advection model of Smith (2003). The vertically-integrated steady-state governing equations are solved using Fourier Transform techniques. Four length scales are included: mountain width, a mountain wave scale, the moist layer depth and a cloud drift distance. The amount of precipitation in the model is limited by the decay of the forced ascent through the moist layer and by the advection of condensed water downstream into the region of descent. The strong influence of horizontal scale, predicted by the model, is investigated. Closed form expressions are derived for special cases.
Session 6, Orographic Precipitation I
Wednesday, 25 June 2003, 8:30 AM-10:15 AM
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