EFFECTS OF UPPER AND LOW-LEVEL JETS AND CONDENSATION PROCESS OF MOISTURE ON EVOLUTION OF OCCLUDED FRONTAL CIRCULATION

The evolution of occluded frontal circulation and variation of precipitation intensity in upper-level westerly jet and low-level sout herly jet are simulated by using a primitive equation model including moisture condensation process and turbulent dissipation.The calculation results show that the combined effects of moisture condensation process and upper-level jet or low-level jet play a very signif icantrole on the occluded frontal circulation and may be an import ant mechanism for ex citing strong mesoscale deep convection in the occluded frontal zone.In the moist model with moisture condensation process the effects of low-level southerly jet on the occluded frontal circulation are much larger than the upper-level westerly jet and are more import ant to excitest rong mesoscale precipitation in the frontal zone,while in the dry case,as opposed to the moist case,the effects of upper-level westerly jet on the occluded front are much larger.