0704号热带气旋远距离降水的数值模拟诊断分析

NUMERICAL SIMULATION AND DIAGNOSTIC STUDY OF REMOTE PRECIPITATION FROM TROPICAL CYCLONE(0704)

通过对0704号热带气旋远距离降水进行数值模拟诊断分析,发现热带气旋(TC)、副热带高压以及中纬度远距离降水系统三者间可通过副高脊线附近两侧(副高与TC之间、副高与远距离降水之间)的散度风次级环流产生相互作用。结合去除台风的敏感性试验的诊断分析,发现除来自TC的水汽通道外,副高脊以北的散度风次级环流对远距离降水也有重要的影响,该次级环流的强弱与远距离降水的强弱呈正比。此外,通过分析还发现TC作为洋面上的对流性热源可以激发向东北方向传播的准静止波动,这种波动会影响位势高度场的分布,进而也会影响散度风的次级环流,并且当副高脊线向波动的正位相区运动时有利于次级环流与远距离暴雨的加强。

Based on the numerical simulation and diagnostic analysis of Tropical Cyclone Remote Precipitation （TRP） with a particular case, we found that Tropical Cyclone （TC）, Subtropical High （SH） and TRP can interact with each other through a divergence wind secondary circulation located at each side of the ridge line of SH. A diagnostic analysis of the sensitivity experiment removal of TC （0704） indicated that besides moisture channeling from the TC, a non-rotational wind secondary circulation located between the SH ridge line and a remote precipitation zone also has important effect on TRP. The secondary circulation is in proportion to the remote precipitation. In addition, as the convective heat source above the ocean, TC can activate the quasi-stationary wave toward the northeast. This wave can affect the geopotential height field and change the divergence wind secondary circulation. It will have positive effect on the secondary circulation and TRP when the SH ridge line moves to the positive phase of geopotential height of the control test and sensitivity test.