A numerical simulation of the Mei-Yu front and the associated low level jet

Abstract

A two-dimensional frontal model was used to study the structure and behavior of the Mei-Yu front over East Asia. The Mei-Yu front is characterized by mixed midlatitude-baroclinic and tropical-convective properties, with frequent occurrence of a low-level jet (LLJ) that is highly correlated with heavy convective rainfall. The quasi-steady state responses to a large-scale stretching deformation forcing were obtained by integrating the perturbation equations from an initial state of seasonal-mean zonal flow. The midlatitude front extends deeply into the upper troposphere with a strong poleward tilt, whereas the subtropical front is confined to the lower troposphere with less tilt, in good agreement with observations. Along the sloping front, slantwise updrafts develop with a multiband structure. This updraft is more evident in the subtropical cases and in the more moist midlatitude cases. -from Authors