登陆北上山东台风暴雨非对称分布的成因对比分析

应用常规气象观测资料、NCEP 1°×1°再分析资料，选取登陆北上山东地点相近但暴雨落区分别位于台风中心西北侧和东北侧的两个台风，分析暴雨落区相对台风中心非对称分布的成因。结果表明：台风进入中纬度以后，0421号台风“海马”位于高空深槽前，与西风槽相互作用，西风槽携带的冷空气从西北侧侵入台风环流，产生湿斜压锋区强迫抬升、冷暖空气交绥、水汽辐合等因素造成暴雨，暴雨趋于出现在台风中心的西北侧，为高比湿舌前方、较强水汽辐合区与相当位温密集区叠加的区域；而0509号台风“麦莎”与副热带高压相互作用，引起涡度及涡度平流的非对称改变，暴雨区与500 hPa正涡度区或正涡度平流相对应，暴雨趋于出现在台风中心的东北侧，为强正涡度平流区与水汽辐合叠加的区域。

Causal-comparative study of asymmetric distribution of rainstorm by typhoon crossing Shandong

Based on conventional observation data and NCEP 1°×1° reanalysis data, two typhoons, which entered Shandong by close sites but generated quite different rainstorm areas (to the northwest and northeast of the typhoon center, respectively), are analyzed to investigate the causes of asymmetric distribution of typhoon rainstorm. The results indicate that after entering middle latitude region, Typhoon HAIMA (2004) lies in front of upper deep trough and interacts with it, leading cold air intrudes into the typhoon circulation from the northwest side. Forced uplift of wet baroclinic frontal zone, confluence of cold and warm air, and water vapor convergence are generated and result in rainstorm event. The rainstorm tends to occur to the northwest side of the typhoon center, lying in front of high specific humidity and in the superimposed area of stronger water vapor convergence zone and the equivalent potential temperature front zone. By contrast, the interaction between Typhoon MATSA (2005) and the subtropical high brings about the asymmetric change of vorticity and vorticity advection, and the rainstorm area corresponds to the positive vorticity area or the positive vorticity advection at 500 hPa. The rainstorm tends to occur to the northeast side of the typhoon center, which is the superimposed area of strong positive vorticity advection area and water vapor convergence.