【作者】 梁军； 陈联寿； 李英；

【Author】 Liang Jun (Dalian Meteorological Observatory, Dalian, 116001) Chen Lianshou Li Ying (Chinese Academy of Meteorological Sciences, Beijing, 100081)

【机构】 大连市气象台； 中国气象科学研究院；

【摘要】 选取登陆北上在辽东半岛地区形成大暴雨的9216号(Polly)台风为例,采用NCEP全球分析资料,利用MM5中尺度非静力模式,对其环境流场和影响期间冷空气的作用进行诊断分析,并对下垫面海温对Polly的强度、路径、低层辐合和水汽通量及降水的影响进行数值模拟,结果表明,Polly影响期间,有利、稳定的副热带高压使低值系统偏北移动,并靠近中纬度斜压锋区,使低值系统得到发展的同时并阻挡着其东移出海;高空辐散低层辐合相叠置,高空急流在35°N以北,呈非纬向,有利于垂直上升运动的加强和Polly的向北移动;辽东半岛地区为低空急流水汽输送辐合区;登路北上过程中,中纬度斜压锋区穿过Polly,使其获得斜压能量变性发展为温带气旋;黄海北部海面表层温度升高使热带气旋移动路径向海温暖舌区域偏折,低层辐合和水汽输送明显加强,降水量显著增加。更多还原

【Abstract】 Using the Penn State-NCAR nonhydrostatic mesoscale model(MM5) and NCEP reanalysis 2.5-degree grid data, the characteristics of large scale circulation of tropical cyclone storm rainfall turning to the northern Yellow Sea after landfall and the effects of cold air during the course of Polly affecting the Liaodong Peninsula were performed with diagnostic analysis and the influence of sea-surface temperature on intensity, track, low-level convergence, moisture flux and precipitation of Polly was simulated based on MM5. Results show that tropical cyclone torrential rain over Liaodong Peninsula was closely related to large scale circulation and sea-surface temperature of northern Yellow Sea. In the course of Polly affecting the Liaodong Peninsula, the favorable and stable Subtropical High Pressure(STP) made low-pressure system move northward and approach the mid-latitude baroclinic frontal zone, the low-pressure system would be increased in this process. Superimposing of high-level divergence and low-level convergence, high-level jet was situated in the areas north of 35°N and showed itself non-longitudinal wind that were favorable to move towards north of a tropical cyclone and the intensification of vertical ascending motion. Liaodong Peninsula was connected with the convergence field of lower layer moisture transportation which resulted in severe heavy rain over Liaodong Peninsula. In the course of Polly moving towards north, the cold front from northwest passed it and it gained the baroclinic energy from the mid-latitude that caused extratropical transition of Polly and developed extratropical cyclone. The rising of sea-surface temperature in the northern Yellow Sea made Polly move towards the warm tongue field of sea-surface temperature and resulted obvious enhance in low-level convergence and moisture transportation and precipitation.更多还原