The Effect of Critical Levels on 3D Orographic Flows: Linear Regime

摘要: Abstract The effect of a critical level on airflow past an isolated axially symmetric obstacle is investigated in the small-amplitude hydrostatic limit for mean flows with linear negative shear. Only Richardson numbers (Ri) greater or equal to ¼ are considered. authors examine problem using linear, steady-state, inviscid, dynamic equations, which well known exhibit singular behavior at levels, as numerical model that has capability capturing both nonlinear and dissipative effects where these significant. Linear theory predicts 3D wave pattern individual waves confined paraboloidal envelopes below strongly attenuated directionally filtered above it. Asymptotic solutions field far from mountain show large shear-induced modifications proximity level, quickly widen height. Above ...