北太平洋增暖对我国西北秋雨的影响  

Influences of the North Pacific Warming on Autumn Precipitation in Northwest China

作　　者：韩晋平[1] 

机构地区：[1]中国气象科学研究院,北京100081

出　　处：《应用气象学报》2014年第3期257-264,共8页Journal of Applied Meteorological Science

基　　金：国家自然科学基金项目(41005045);中国气象科学研究院基本科研业务费(2013Z002);科技部国际合作项目(2009DFA21430)

摘　　要：利用1979-2012年我国160站逐月降水资料、NOAA全球海洋表面温度资料和NCEP-DOE大气环流再分析资料,采用统计分析方法研究了北太平洋海表增暖对我国西北秋雨年代际变化的影响。结果表明:西北秋雨在2000年前后经历了年代际跃变,1986-1999年为少雨期,2000-2012年为多雨期。进一步分析表明:西北秋雨的年代际变化与北太平洋海表增暖关系密切,北太平洋海温偏暖时,东亚一北太平洋地区的大气温度升高,引起东亚地区的南北温差减弱,使东亚西风急流减弱,急流中心偏北,东亚中纬度地区气压升高,导致异常东风水汽输送带偏强,造成西北秋雨异常偏多。Based on monthly precipitation data from 160 meteorological stations established by National Climate Center in China, NOAA reconstructed extended monthly SST and monthly atmospheric circulation data from NCEP-DOE Reanalysis datasets, the influence of North Pacific sea surface temperature （SST） on autumn precipitation from 1979 to 2012 in Northwest China is studied by using statistical analysis method. An inter-decadal change of the autumn precipitation is found around the year of 2000 by 11-year-running t test. It is in the dry period during 1986-1999 and wet period during 2000-2012 for the region in North- west China. Further analysis shows that the inter-decadal change of autumn precipitation in Northwest China is connected with the warming SST in the North Pacific after 2000. When the SST in the North Pa- cific is in warm phase, the troposphere temperature over East Asia-Northwest Pacific is dramatically increased. The contrast of troposphere temperature between the north and the south over the East Asia- Northwest Pacific is directly associated with the strength of westerly jet and the geopotential high anoma- lies over the region. The warming of troposphere temperature over East Asia-Northwest Pacific weakens the atmospheric thermal contrast between the mid-low latitudes and the polar area in the East Asian region. Influenced by the decreased thermal contrast along East Asia region, the westerly jet over the East Asia-Northwest Pacific is reduced significantly. And the westerly jet center at middle latitudes near the East Asian coast shifts northward. The warming in troposphere circulation and the north shifting of weakened westerly jet tend to make the geopotential high along East Asian coast increase significantly. In other words, the trough at 500 hPa along the East Asian coast is weakened, which is characterized as an anoma- lous anticyclone at 500 hPa. The anomalous wind flows at 850 hPa in the south of the anticyclone are easterlies. As a result, the water vapor transported by anomalous easterlies

关 键 词：我国西北秋雨 北太平洋海温 年代际变化 

分 类 号：P461.2[天文地球—大气科学及气象学]