摘要
2008-2009年冬季,我国北方冬麦区发生了特大干旱灾害。利用NCEP/NCAR的再分析资料,分析了干旱发生过程中气温的异常、垂直积分的水汽含量特征和水汽输送的变化,最后从大气环流角度分析了干旱发生的内在原因。结果表明:2008-2009年冬季,我国中部和华北部分地区气温偏高,华北以北地区气温偏低,冷空气活动频繁;从印度洋到我国西南、中部、华北地区的水汽含量比多年平均偏少,我国大部分地区气流比较平直,西南方向的偏西风水汽输送较弱。在干旱发生过程中,乌拉尔山、巴尔喀什湖为高压脊,贝加尔湖到中纬度地区为槽区,亚洲大陆的东部又为高压脊;亚洲中部和东亚以经向型环流为主,贝加尔湖到西伯利亚地区为明显的负距平,有利于冷空气南下影响我国北方地区。同时,我国大部分地区下沉气流较多年平均偏强,从青藏高原南侧到西南、华南地区的下沉气流减弱了西南方向的偏西气流水汽输送,从而导致降水减少。
A severe drought occurred in north China in winter of 2008 - 2009, and it resulted in serious economic loss and social problems, especially in Shanxi, Hebei, Henan and Anhui provinces. The NCEP/NCAR reanalysis data downloaded from the Earth System Research Laboratory of NOAA and the mean monthly precipitation data observed by 160 meteorological stations are used to research the abnormal change of air temperature, vertical air vapor content and air vapor transport during the severe drought. The results are as follows ： （ 1 ） In winter of 2008 - 2009, air temperature was relatively high in central China and north China but low in the northern part of north China; （2） The vertical air vapor content was lower than the multi-year average over the Indian Ocean, southwest China, central China and north China during the severe drought, airflow transport was nearly straight over the most regions of China so that it was weaker than the average; （3） During the severe drought, there were the continuing block high over the Balkhash and Ural regions, pressure trough over the Lake Baikal region, and high over East Asia. The main airflow over Central Asian and East Asian was a meridional circulation. The circulation fields were conducive to the southward cold air to north China; （4） Subsiding airflow was stronger than the multi-year average over the most regions of China. Vapor transport from the Indian Ocean was weakened by the strong subsiding airflow over the Qinghai-Tibetan Plateau, southwest China and south China. These results can provide some theoretical bases and useful references for researching severe drought.
出处
《干旱区研究》
CSCD
北大核心
2010年第2期182-187,共6页
Arid Zone Research
基金
成都信息工程学院科研启动项目(KYT200708)
中国气象局成都高原气象开放实验室基金课题(LPM2008005)共同资助
