西北地区3—9月降水量与ENSO的联系

Association of Precipitation over Northwest China during March to September with ENSO

利用1950—2005年全球陆地月平均降水资料,分析了中国西北地区3—9月平均降水量(Rm)与ENSO的统计关系。结果表明:在全球变暖背景下,厄尔尼诺当年(次年)西北地区Rm偏少(偏多)的关系依然稳定存在,并且随着全球增暖,该关系表现得更稳定。西北地区,尤其是西北地区东部是同纬度带主要干旱半干旱区中Rm与ENSO联系最紧密、最稳定的区域。北半球主要干旱半干旱区中,厄尔尼诺当年Rm偏少,次年Rm偏多的关系仅存在于中国北部地区。我国西北地区东部厄尔尼诺事件当年(次年)Rm偏少(偏多),我国西北地区西部38°N以南厄尔尼诺事件当年(次年)Rm偏多(偏少),存在着明显的东西部差异。

By using 1950-2005 global land monthly precipitation, statistical relationship between precipitation over Northwest China during March to September （Rm） and ENSO was analyzed. Results show that the relationship of less Rm in Northwest China in the El Nino year and more Rm in the subsequent year existed stably, and with global warming, this relationship has become more stably. Northwest China, especially its east part, is the area where Rm is closest and most stably related to ENSO compared with other main add and semi-add areas in the latitude band of Northwest China. Northern China is the only region among the add and semi-add regions in the Northern Hemisphere where Rm is less in the El Nino year and more in the subsequent year. There is less/more Rm in the El Nino/subsequent year over the east part of Northwest China, while more/less Rm in the El Nino/subsequent year in the west part south of 38°N,and thus obvious difference exists between the east and west part of Northwest China.