Laterally Driven Stochastic Motions in the Tropics

Publisher Website
Google Scholar
Abstract
A two-layer dry atmospheric model containing non-geostrophic effects and parametrized dissipation is used to investigate the large-scale tropical eddies as perturbations on a basic state which has empirical static stability and symmetric zonal current. The perturbed motion is treated as a stationary random process driven by stochastic forcing at ±30° latitude. The latter is inferred from observations at 30N. In the predicted internal statistics, 1) variance of horizontal velocity components is much larger at the upper level and decreases equatorward, 2) variances of horizontal divergence and of temperature decrease markedly equatorward, and 3) the eddies transport sensible heat and wave energy equatorward, and transport zonal momentum poleward. The eddies gain kinetic energy from pressure work on the boundaries and lose it by dissipation and conversions to zonal kinetic energy and eddy available potential energy, which is in turn depleted by radiative cooling and conversion to zonal available pot... Abstract A two-layer dry atmospheric model containing non-geostrophic effects and parametrized dissipation is used to investigate the large-scale tropical eddies as perturbations on a basic state which has empirical static stability and symmetric zonal current. The perturbed motion is treated as a stationary random process driven by stochastic forcing at ±30° latitude. The latter is inferred from observations at 30N. In the predicted internal statistics, 1) variance of horizontal velocity components is much larger at the upper level and decreases equatorward, 2) variances of horizontal divergence and of temperature decrease markedly equatorward, and 3) the eddies transport sensible heat and wave energy equatorward, and transport zonal momentum poleward. The eddies gain kinetic energy from pressure work on the boundaries and lose it by dissipation and conversions to zonal kinetic energy and eddy available potential energy, which is in turn depleted by radiative cooling and conversion to zonal available pot...

This publication has 0 references indexed in Scilit: