1961—2010年云南省基于SPEI的干旱变化特征分析

Characteristics of drought based on standardized precipitation evapotranspiration index from 1961 to 2010 in Yunnan province

利用1961—2010年云南省29个气象站逐月降水和气温资料,选取综合降水和气温变化共同效应的新的干旱表征指标—标准化降水蒸发指数(SPEI)计算云南省各地区平均SPEI-12,并对1961—2010年云南省干旱演变特征、干旱发生频次、干旱持续时间和干湿变化周期进行了分析。结果表明:进入21世纪后,云南各地区干旱持续时间和干旱程度均明显增加,尤其滇东北和滇东南地区增加最显著;降水是影响云南省干旱的主要因素,但气温的升高加剧了云南地区干旱化的趋势;21世纪前10 a云南地区总干旱事件和严重及以上程度干旱事件的发生次数均显著增加;云南省多发生持续时间超过6个月的干旱;通过小波分析可知,云南省干湿变化表现为5 a左右的振荡周期,且未来几年云南地区仍表现为干周期。

Based on monthly precipitation and air temperature data at 29 weather stations in Yunnan province from1961 to 2010,mean SPEI-12（ standardized precipitation evapotranspiration index） was calculated by a newdrought index SPEI which is a multi-timescale drought index not only considering precipitation but also air temperature. Characteristics of drought evolution,drought occurrence frequency,drought duration and dry-wet change period in Yunnan province were analyzed. The results indicate that duration and degree of drought in Yunnan province increase significantly since the 21 st century,especially in the northeast and southeast. Precipitation is the main factor affecting drought,and rising temperature strengthens drought in Yunnan province. During the first decade in the 21 st century,the total number of drought events and the number of severe and above degree drought events are in significantly increasing trends. Drought duration more than 6 months often occurs in Yunnan province. An oscillation period of dry-wet change is about 5 years by a wavelet analysis,and it is estimated that it will be the dry period in the next fewyears.