A Mesoscale Numerical Simulation of Low Level Jet Realted with the Southwest Vortex
一次与西南低涡相联系的低空急流的数值研究

Using a mesoscale model,a numerical simulation on the low-level jet accompanying the southwest vortex is performed. Results show that the formations and developments of this southwest vortex and the accompanying low-level jet are closely related with the middle level divergence in the beginning;the low-level jet moves eastward and develops prior to the southwest vortex in the west of the Daba Mountain;the south component of horizontal wind contributes more significantly to the evolution of the low-level southwest jet;the strengthen center of south component which locates in front of south component center causes south component center moving eastwerd. Computations of various terms of south wind momentum budget reveal that the horizontal advection and generation term play prominent roles in the strengthen of the south component,and the horizontal and vertical advection have adverse effects;the Coriolis force cannot be ignored with negative effects,the planetary boundary layer term should be considered in some stage and area, the other terms have little effects.