基于SPEI的东北地区气象干旱风险分析

Risk analysis of meteorological drought in Northeast China based on standardized precipitation evapotranspiration index

文中依据东北地区91个气象站1961-2012年的月均温和月降水量数据,计算多时间尺度的标准化降水蒸散指数(SPEI),并采用Theil-Sen斜率估计方法和Copula函数,分析了东北地区近52a来的干旱时空变化特征及干旱风险的空间格局。结果表明:1)1990s以来,不同时间尺度的干旱事件频率均出现较大幅度的增加,尤其是重旱、特旱级别的干旱事件;2)在空间上,几乎整个东北地区的干旱事件发生频率均呈现显著增加趋势,其中内蒙古东部和吉林省西部平均增加幅度最大;3)呼伦贝尔市周边、白城西部、科尔沁沙地、鹤岗-佳木斯-鸡西一线的干旱风险较高,长白山地区、三江平原和黑龙江省西南部的干旱风险较低。文中研究结果可以为东北地区干旱监测计划的制定及旱灾风险评估提供理论依据。

The multi-scale standardized precipitation evapotranspiration index（ SPEI） was calculated according to monthly mean temperature and monthly precipitation records from 91 meteorological stations in Northeast China during 1960-2012. The spatio-temporal characteristics of drought in the nearly 52 years were investigated and the spatial pattern of drought risk were also mapped based on Theil-Sen slope estimation method and Copula function. The results show that：（ 1） The drought frequencies for different time scales all increased obviously since the 1990 s,especially for the severe and extreme drought events.（2） The drought frequencies showed a significant increase in most of the Northeast China and the average increases in the eastern part of Inner Mongolia and western Jilin province were the largest.（ 3） Areas surrounding the Hulunberer,western Baicheng city,Horqin sandy land and Hegang-Jiamusi-Jixi were associated with a higher drought risk,while areas with lower drought risk were noted for Changbai Montains,Sanjiang Plain and the southwest of Heilongjiang province. The results of this study could be helpful for establishing drought monitoring plans and assessing drought risk in Northeast China.