全球陆地年降水量与ENSO关系的初步研究

摘要

用全球陆地月降水资料(PREC/L),研究了1948-2000年期间的ENSO事件与全球陆地年降水量的关系.对合成分析的结果进行了蒙特卡洛模拟检验.结果表明,暖事件年全球陆地年降水量大范围地明显减少,显著的地区是:赤道西太平洋区,中国的华北,赤道中美洲区,孟加拉湾北部及尼泊尔,东澳大利亚区,印度西部及巴基斯坦南部,勒拿河以东地区,西欧及南极的威尔克斯等区域.在暖事件年,陆地年降水量增加地区不多,主要是南美的智利和阿根廷,东非索马里,肯尼亚和坦桑尼亚,中东的土耳其,伊拉克及伊朗,北非的利比亚和阿尔及利亚,西南非的纳米比亚及非洲南部的博茨瓦纳和津巴布韦.统计检验表明,暖事件年全球陆地年降水量减少的面积比降水量增加的面积要大,而且更为显著.将本文结果与早期的研究结果进行了比较.研究还指出,ENSO的年代际变化对上述地区降水的年代际变化影响不明显.但是80年代以后的暖事件对东澳大利亚干旱,中国的华北的干旱的影响比80年代前的影响更大.%The global land monthly precipitation data (PREC / L) are used to investigate the relation between the global land annual precipitation and ENSO during 1948-2000, and the results of composite analysis are tested with Monte Carlo simulations. Results indicate that the global land annual precipitation was significantly reduced in large scale areas in warm event years;, the areas were the equatorial West Pacific, North China;equatorial Central America; North Bengal Bay and Nepal; East Australia; West India and South Pakistan;the district east of the Lena River; West Europe; and Wilkes Land of Antarctica. In contrast to this, the areas where precipitation increased in warm event years were less, and mainly in Chile and Argentina of South America; Somali, Kenya, and Tanzania of East Africa; Turkey, Iraq, and Iran of the Middle East; Libya and Nigeria of North Africa; Namibia of Southwest Africa; and Botswana and Zimbabwe of southern Africa. Statistical tests show that in warm event years, the area where the land annual precipitation was reduced was larger than the area where the annual precipitation increased, and the reduction in precipitation was more significant than the increase. The results in this paper are compared with previous studies. It is also pointed out that the interdecadal change of ENSO had no significant effect on the interdecadal variation of precipitation in the above regions. However, the warm events of El Nino affected the droughts in East Australia and North China more after the 1980s than before.