摘要
利用1998--2010年逐日08：00、20：00（北京时）500hPa高空图、日雨量和青藏高原（下称高原）低涡切变线年鉴，分别对近13年冬、夏半年高原切变线的活动情况及其对中国降水的影响进行了天气诊断和统计分析。结果表明，冬、夏半年高原切变线是以横切变线为主，且以东部切变线占绝大多数。冬半年高原切变线主要出现在3、4月，4月有五分之一能移出高原；夏半年高原切变线主要出现在5—9月，8—9月有五分之一能移出高原。冬半年，24h以上活动时间的高原横切变线与12h以上活动时间的竖切变线可造成高原中雪天气。夏半年，高原切变线随着活动时间的增长，影响高原和中国其他地区的降水范围和强度在增大，24h以上活动时间的高原竖切变线可造成高原暴雨及其周边地区出现小雨以上的降水；还有一半以上年份，每年有1次可影响到中国中部并产生中雨到大暴雨。48h以上活动时间的高原横切变线在高原上可造成暴雨以上的降水，甘肃、四川盆地中雨以上的降水；绝大多数年份每年有1～3次移出高原的横切变线，可影响到中国西南部、中部产生暴雨以上的降水，有的可影响到华东、华南及华北产生暴雨或大暴雨。
Using the daily rainfall data, 500 hPa synoptic map of 08：00 and 20：00 （Beijing time） and the Qinghai-Xizang Plateau（QXP） vortex and shearline yearbooks from 1998 to 2010, the activities of the plateau shearlines in the winter and summer-half years, and their influences on the rainfall in China, are analyzed with the statistical and synoptic methods. The results show that the plateau shearlines are mostly quasi-zonal shearlines during the summer and the winter half-year and eastern shearlines are the majority. The winter half-year plateau shearlines mostly appear in March and April, and one fifth of them can move out of the QXP in the month. The plateau shearlines in winter half-year are less and are about one fifth of the whole year number. But quasi-zonal shearlines with 24 h lifetime and quasi-longitudinal shearlines with 12 h lifetime can lead to middle event snow or rain in the QXP and nearby provinces. Especially the quasi-zonal shearlines with 24 h lifetime not only lead to the medium snow or rain in and near to the QXP, but also influences the far from the QXP and lead to medium- and heavy-rain there. Longer lifetime the plateau shearlines have in summer half-year, larger region and intensity of precipitation in and near to the QXP happens. Those quasi-longitudinal in the summer half-year with 24 h lifetime can cause the rainstorm in the QXP, medium rain in Gansu Province and little rain in Sichuan basin and Yunnan Province. And in more than half of the year, the shearline can cause medium or severe rain in Shanxi, Henan, Shanxi, Chongqing and Guizhou at least once a year. The quasi-zonal plateau shearlines, which last for more than 48 h, can cause rainstorm in the QXP, medium or severe rain in Gansu Province, the heavy rainstorm in Sichuan Basin and little rain in Yunnan Province. And in most of the year, one to three times the shearline can cause rainstorm or more in Guizhou, Hubei, Shanxi and Chongqing, some even can cause rainstorm or heavy rainstorm in Anhui, Jiangxi, Gangxi, Guangdong and Henan.
出处
《高原气象》
CSCD
北大核心
2013年第6期1527-1537,共11页
Plateau Meteorology
基金
国家重点基础研究发展计划(973计划)(2012CB417202)
国家科技基础性工作专项项目(2006FY220300)
关键词
高原切变线
横切变线
竖切变线
降水
Plateau shearline, Quasi-zonal , shearline, Quasi-longitudinal , shearline, Precipitation
