基于SPI指数的黑河地区5—9月干旱趋势分析

利用黑河地区1968—2015年5—9月的降水资料对时间尺度为12个月的SPI指数进行了计算,探讨了黑河地区干旱发展特征及变化趋势。结果表明,近48年内SPI最大值出现在2013年,最小值出现在2008年;2007年以后总趋势在向干旱发展,2015年前后达到顶点,未来几年黑河地区有向干旱发展的趋势。从旱涝趋势的变化周期来看,16年的时间尺度为旱涝变化的第1主要周期。2015年黑河地区处于丰水期,预计未来将逐渐向枯水期转换。干旱指数变化的突变点发生在1980年,20世纪80年代以后转入多水年,2000年以后,趋势向少水发展,到2010年前后,再次出现突变点,气候转向湿润。从黑河地区干旱发生频次来看,20世纪80年代开始,中旱和重旱频次一直在增加,到2000—2010年,旱情达到最重,中旱和重旱频次显著高于其他年代。

Drought Tendency Based on Standardized Precipitation Index( SPI) in Heihe Area from May to September

We calculated the standardized precipitation index(SPI) of time scales for 12 months by using the precipitation data in Heihe area from May to September during 1968-2015,and discussed the development characteristics and trends of drought in Heihe area.The results showed that in the past 48 years,the maximum value of SPI appeared in 2013,and the minimum value appeared in 2008.Since 2007,the general trend was to the development of the drought,and the peak was around 2015,in the next few years in Heihe area had to be the trend of the drought.From the perspective of the change cycle of drought and flood trend,16 years of time scales was for the first major cycle.In 2015,Heihe area was in the wet cycle,and the future was expected gradually to the dry season conversion.The change-point of drought index took place in 1980,after 1980s, the trend toward the development of wet cycle,after 2000s ,the trend to developed less water,by 2010 before and after,there would be a sudden change point,the weather turned to wet.From the frequency of the drought in Heihe area,since 1980s,the frequency of the moderate drought and the heavy drought had been increasing,until to 2000 -2010,the drought reached the most drought,the frequency of moderate drought and the heavy drought was significantly higher than other years.