西北太平洋台风对西北地区东部降水的影响分析

采用1961—2000年NCEP/NCAR资料、台风路径资料和西北东部48个代表站的降水资料,分析研究了台风与西北东部降水的相互关系。发现台风有利于西北东部降水的产生,敏感区位于河套;在多台风年,副热带高压位置偏北偏弱,西北东部盛行偏南风,有利于降水的产生;在少台风年,副热带高压偏南偏强,西北东部盛行偏北风,不利于降水的产生;台风活动期内,副高会西伸北抬,与西风槽、低涡、切变线共同造成西北东部降水的出现;通过建立台风对西北东部降水影响的天气概念模型,发现在台风活动期内,西北东部多锋面降水天气。

Impact of Northwest Pacific Ocean Typhoon on Precipitation in Eastern Northwest China

The NCEP/NCAR global reanalysis data,the typhoon path data and the precipitation data at 48 stations in the eastern area of northwest China during 1961 to 2000 were used to study the relationship between the typhoon and the precipitation in the eastern area of NW China. It is discovered that typhoon is favorable for the precipitation in eastern Northwest China, Hetao area Ningxia is the sensitive area. In more typhoon years, the SUBH (subtropical high) extends quite further north and weaker than the usual, and the south wind in eastern NW China is strong and it provides advantages for rainfall; in less typhoons years, the SUBH shrink south and stronger than the usual, so the north wind is strong and it's disadvantageous for rainfall. In the period of typhoon, the SUBH stretches west and move north, with the westerly trough, low vortex, shear line that jointly caused the precipitation in eastern NW China. From weather concept model established for the influence of typhoon on precipitation in eastern of NW China, it is found that there are more cold front and frontal surface precipitation in the east of NW China.