高低空急流和水汽凝结过程对锢囚锋环流演变的影响

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

中文关键词:  高低空急流  凝结过程  锢囚锋环流

英文关键词:Upper and low-level jets  Condensation process  Occluded frontal circulation

中文摘要:

      文中利用包括湍流摩擦耗散的原始方程模式研究了高空西风急流、低空南风急流和水汽凝结过程对锢囚锋环流时间演变和降水强度变化的影响,计算结果表明,水汽凝结过程与高空西风急流或低空南风急流的共同作用对锢囚锋环流的演变起非常重要的作用,能在锢囚锋区形成强中尺度深对流系统,与干大气中高空西风急流对锢囚锋环流的作用远大于低空南风急流的情况相反,在存在水汽凝结过程的湿大气中,低空南风急流对锢囚锋的影响远大于高空西风急流,它产生的降水过程时间更长,降水强度更大,降水范围更广,是锢囚锋区产生强中尺度降水的重要因子。

英文摘要:

      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.