基于SPEI指数的辽宁省多尺度旱涝特征分析

近年来辽宁省深受旱涝灾害的影响,明确其时空演变特征对进一步制定防灾减灾策略具有重要意义。利用1989—2018年辽宁省23个气象站点逐日气象数据,基于不同时间尺度的标准化降水蒸散指数(SPEI指数),运用Mann-Kendall突变检验、线性倾向率等数理统计方法,对辽宁省近30年来旱涝演变及持续性特征进行分析,并结合通径分析方法探究其影响因素。结果表明:(1)近30年来辽宁省经历涝-旱-涝的演化过程,辽西干旱化显著,变涝趋势最显著的是辽中和辽北,其次是降水量最丰富的辽东;(2)从中度及以上旱涝灾害频率看,1999—2008年为典型的干旱时段,而2009—2018年则为偏涝时段,旱涝事件发生频率春季冬季秋季夏季;(3)持续性干旱事件强度变小,主要发生在春季。持续性洪涝事件呈增加趋势,主要发生在春、夏两季;(4)降水量是影响旱涝变化的主要因素,蒸散量次之,气温是通过影响降水量和蒸散量进而影响旱涝变化的。

Analysis of multi-scale drought and flood characteristics in Liaoning Province based on SPEI

In recent years,Liaoning Province has deeply been affected by drought and flood disasters. It is of great significance to make clear the spatiotemporal evolution characteristics for the disaster prevention and mitigation strategies. The evolution and persistence characteristics of drought and flood in Liaoning Province in recent 30 years were analyzed, and their influencing factors were explored by using Mann Kendall mutation test, linear tendency rate and path analysis based on the daily meteorological data of 23 meteorological stations in Liaoning Province from 1989 to 2018, in which the standardized precipitation evapotranspiration index (SPEI) of different time scales was calculated. The results show that:(1) Liaoning Province has experienced the evolution process of waterlogging, drought and waterlogging in recent 30 years. The drought in western Liaoning is significant, and the trend of waterlogging is the most significant in central and Northern Liaoning,followed by Eastern Liaoning where precipitation is the most abundant. (2) The period of 1999-2008 is the typical drought period, and 2009-2018 is the partial flood period from the frequency of moderate and above drought and flood disasters. The frequency of drought and flood events is spring > winter > autumn > summer. (3) The intensity of persistent drought events decreases,which mainly occurred in spring. The continuous flood events show an increasing trend, which mainly occurred in spring and summer. (4) Precipitation is the main factor affecting the change of drought and flood,followed by evapotranspiration. The temperature affects the change of drought and flood by affecting precipitation and evapotranspiration.