2009年秋至2010年春我国西南地区干旱及与历史场次干旱对比分析

2009年10月至2010年4月,我国西南地区由于受厄尔尼诺影响,气温偏高、降雨偏少,发生了秋冬春三季连旱,耕地受旱面积占全国同期耕地受旱面积的78%,受灾人口和大牲畜饮水困难头数都达到了近十年来该地区的最高水平。通过对比本次和历史场次干旱发现,西南干旱并非稀遇现象,1951~1990年的40年间该地区曾发生干旱12次,且1949年以来,干旱有缓慢加重的趋势;本次旱灾与1963年旱灾在时空分布、灾害成因和灾情方面较为相似,但从气象干旱的角度来看,虽然1963年部分受旱地区无有效降雨历时为11个月,高于本次旱灾的6个月,但本次受灾率和成灾率均为1949年以来的最大值,说明在快速发展背景下,经济社会面对干旱显得更为脆弱。这些结论对于认清西南地区干旱特性与旱灾演变规律,加强抗旱减灾体系建设,具有重要的参考价值。

Drought in Southwest China from Autumn 2009 to Spring 2010 and Its Comparative Analysis with Historical Drought Events

A heavy drought caused by El Nio occurred in southwest China with higher temperature and less rainfall from October 2009 to April 2010.Statistics show that the affected area of farmland approaches 78% of that in-all China in corresponding period,and the number of affected population and livestock is up to the peak value in the last decade.This paper indicates that drought occurring in southwest China is not accidental,five provinces in southwest China had suffered dozen drought events simultaneously from 1951 to 1990,and drought had become more frequent in recent decades since 1949.This drought disaster is similar to that in 1963 in temporal and spatial distribution,cause of formation and loss.But from the viewpoint of meteorological drought,the duration of non-effective rainfall in partial area was 11 months in 1963,which is longer than corresponding 6 months in this drought.While the drought affected ratio and disaster-formative ratio of this drought are maximum since 1949.So the research shows that our society becomes more vulnerable to drought under the background of economic high-speed development.These conclusions are helpful to understand drought characteristics and evolution,and strengthen the construction of drought disaster prevention and reduction.