摘要:利用欧洲气象中心（ERA-interim）再分析资料以及中国气象局观测站点的实况降水观测结合CMORPH卫星反演的逐时降水资料，对比分析了路径类似的1513号台风Soudelor和1410号台风Matmo在登陆福建前后期间的降水分布特征以及造成登陆台风暴雨强度和落区差异的原因，得到以下初步结论：Soudelor和Matmo移动路径相似，但在登陆福建的过程中对浙、闽地区造成的降水强度和分布差异明显，如Soudelor造成的总降水强度比Matmo大，且Soudelor的强降水在登陆前主要分布在台风路径的右侧，台风中心的偏北方向，登陆以后主要在台风的偏北以及东北方向；而Matmo登陆前降水基本均匀分布在路径两侧，强降水区位于台风中心的西北方向，登陆福建以后向北移动的过程中强降水区转向台风中心的北边；不同的大尺度环流背景也会导致登陆过程中不同的降水分布特征，Soudelor影响期间副热带高压比较强盛，并阻断它与中纬度西风槽的作用，而Matmo登陆北上过程中逐渐减弱并汇入河北上空的西风槽中，所以登陆后期Matmo的降水比Soudelor强；Soudelor和Matmo台风登闽前后低层水汽输送及东风急流差异是导致大暴雨落区差异的原因之一，Matmo的水汽输送主要来自孟加拉湾及南海，而Soudelor登陆前东部有来自另一个台风Molave的水汽输送，登陆后强水汽输送通量区及水汽辐合带位于Soudelor偏北侧，这与Soudelor登陆造成的暴雨在中心偏北方向一致；南亚高压相对于台风的位置也会影响降水，Soudelor登陆时，大兴安岭上空大槽前的偏西风急流与南部高压西北侧的西南急流一起使得它登陆后减弱速度变缓，有利于台风暴雨的维持，而Matmo高空受急流造成的气旋性切变流场加速了台风的减弱；此外，台风自身的结构和强度变化以及登陆后维持时间不同也是造成两次过程降水差异的主要原因之一，台风暖心结构的强度以及台风高层暖心减弱的速度对台风降水有一定影响，但对登陆时台风暴雨的不对称分布影响较小；Soudelor登闽过程中，涡度场强度比Matmo大，且维持一个深厚的垂直对称结构，登闽后期附近的辐合上升气流主要位于中心东侧，而Matmo在登闽过程中，低层的强辐合区和上升运动区始终偏西，造成二者降水分布的不同。
关键词:登陆台风/
暴雨结构演变/
水汽输送/
对比分析
Abstract:Different characteristics of typhoon Soudelor (1513) and typhoon Matmo (1410) are analyzed before and after they made landfalls in Fujian based on reanalysis data of the ECMWF ERA-Interim and CMORPH data (which is derived from station observations and satellite retrievals of precipitation). The two typhoons shared similar tracks but showed different features of precipitation intensity and distribution. The results indicate that the discrepancy between rainfall distributions of the two TCs (tropical cyclone, the same hereafter) is much more evident after they made landfalls in Fujian Province. And one of the primary causes is the difference in the intensity and maintenance time after their landfalls. Furthermore, differences in large-scale circulation background may lead to different consequences. For Soudelor, the large-scale steering flow of the subtropical high was strong enough to cut off the interaction between Soudelor and the mid-latitude westly trough. However, the steering flow was relatively weak for Matmo, and thus it moved into the mid-latitude trough while passing by Hebei Province, resulting in precipitation enhancement. Besides, changes of heavy rainfall area were related to differences in low-level moisture transport and jet flow. For Matmo, the water vapor mainly came from the Bay of Bengal and the South China Sea, whereas Soudelor took water vapor transported from another tropical storm Molave (1514). Sufficient water vapor transport and distinct moisture convergence zone were locate to the north or northeast of Soudelor. In addition, the position of the typhoon with respect to the South Asia high also affected the location of the torrential rain area. The weakening of Soudelor after its landfall was slowed down by the joint effects of the westerly jet stream in front of the trough over the Greater Khingan Mountains and the southwesterly jet stream on the northwestern side of the South Asia high. In contrast, the cyclonic shear flow created by the upper-level jet accelerated the extinction of Matmo during its northward movement process. The result also shows that the difference in the dynamic structure of the typhoons before and after their landfalls is another reason for the different characteristics of precipitation distribution. The decrease of the warm core intensity of Soudelor was much more distinct during its landing, yet the vertical structure of the vorticity maintained deep and symmetric and stronger than that of Matmo. The dominant area of strong convergence and updraft was located to the east of the center of Soudelor, especially in the late stage of its lifetime, whereas the area was deflected to the west of the center of Matmo throughout its landing process.
Key words:Landfall typhoon rain/
Comparative analysis/
Evolution of structure/
Transport of water vapor
PDF全文下载地址:
http://www.iapjournals.ac.cn/dqkx/article/exportPdf?id=2f43bc8d-7d99-42cd-ac41-67a947a6e555
