基于SPEI的鲁西北地区干旱变化特征

Research on Drought Change Characteristics in Northwest Shandong Province Based on SPEI

使用鲁西北地区24个国家气象观测站1981—2017年的气温及降水月值数据,主要通过计算年尺度SPEI指数,采用线性回归、两种突变检验方法以及小波能量谱分析等方法深入分析鲁西北地区干旱的变化规律。鲁西北地区实际发生的干旱事件与同期同时长SPEI值表征的干旱状态较吻合,表明SPEI指数在该地区具有较好的适用性;鲁西北地区整体上呈不显著的湿润化趋势发展,2008年为研究时间段内干旱情况的突变年;鲁西北地区SPEI12指数多年平均值为正常状态,最小值和最大值分别出现在1990年和2002年。鲁西北地区整体上出现轻旱、中旱、重旱,年份数分别为5次、8次、1次,所有年份均未发生特旱;鲁西北地区不同地区发生不同等级干旱灾害的频率差异较大,整体上干旱灾害的发生频率为轻旱>中旱>重旱>特旱;鲁西北地区年尺度干旱的小波波动能量中心共有3个,中心尺度分别为5 a、9~10 a和3 a。

In order to explore the change characteristics of drought disaster in northwest Shandong Province, we used standardized precipitation evapotranspiration index(SPEI) to monitor and analyze the change rule of drought disaster in this area. Based on the monthly temperature and precipitation data of 24 national meteorological stations in northwest Shandong Province from 1981 to 2017, we deeply analyzed the change rule of drought disaster in northwest Shandong Province by calculating the annual scale SPEI, linear regression, two mutation test methods and wavelet energy spectrum analysis. The results show that the actual drought events in northwest Shandong Province are consistent with the drought state characterized by long SPEI value at the same time, indicating that SPEI index has good applicability in this area. The northwest Shandong Province shows an insignificant trend of wetting on the whole, and 2008 is a sudden change year of drought in the study period. The multi-year average value of SPEI12 index in northwest Shandong Province is normal, and the minimum and maximum values appeared in 1990 and 2002 respectively. The years of mild drought, moderate drought and severe drought in northwest Shandong Province are 5 times, 8 times and once respectively, and no special drought occurred in all years. The frequency of drought disasters of different grades varies greatly in different regions of northwest Shandong Province. On the whole, the frequency of drought disasters is light drought > medium drought > heavy drought > special drought. There are three wavelet wave energy centers of annual drought in northwest Shandong Province, and the central scales are 5 a, 9~10 a and 3 a respectively.