Formation of low-level meso-scale southwest jet during seasonal rainfall

The meso-scale feature and energy budget of a low-level southwest jet were analyzed using the data collected during the heavy rainfall events that occurred between July 20 ～ 27, 1998 over the basin of the Changjiang.And the dynamic mechanism for the formation and maintenance of the meso-scale low-level jet under the condition of the low-level heterogeneous large-scale south wind was investigated using a shallow water model. The results can explain the mechanism of the formation of the meso-scale jet in this event and the importance of the heterogeneous large-scale horizontal motion in the formation of the meso-scale jet.