A Numerical Study of Physical Processes Affecting Convective Cellular Geometry

[摘要] A two-dimensional nonlinear numerical model of cellular convection has been developed in order to investigate the effects of anisotropy of eddy diffusivity, large-scale subsidence, and latent heat release upon the degree of cell flatness. Each of these physical factors has been shown to increase the cellular aspect ratio from that typical of small-scale cumulus to values considerably greater than unity, more comparable to that of mesoscale cellular convection (MCC). The dry convective form of this model agrees well with previous laboratory and numerical findings for classical Boussinesq convection.The model also shows that the preferred aspect ratio more closely simulates a square root relationship to the degree of anisotropic diffusivity (as postulated by Priestley) than that predicted by linear theory.

[学科分类] 大气科学