基于SPI/SPEI的锡林郭勒盟干旱变化特征

Characteristics of Drought Change in Xilin Gol League Based on SPI/SPEI

近年来,干旱现象频发,对锡林郭勒盟生态系统、畜牧业发展造成严重影响,对区域经济发展产生巨大威胁。利用1980~2018年研究区内15个气象站点的逐月累积降水量和月平均温度,采用标准化降水指数(SPI)和标准化降水蒸散发指数(SPEI)分析锡林郭勒盟干旱时空特征,对比了SPI、SPEI在干旱监测中存在的差异。结果表明,1980~2018年锡林郭勒盟持续性干旱事件频发,随着年代的变化连续性干旱事件的发生频次、持续时间均呈增加趋势;研究区干旱频次在空间分布上始终处于动态变化中,中东部和西部地区的干旱发生频次较高,干旱频发区逐渐向西部转移,从东向西干旱发生频次逐渐增加;随着温度上升,SPI对干旱的监测能力开始下降,特别对重旱、特旱的监测能力明显不足,而SPEI对异常干旱的监测能力较强,不易受到降水因素的影响,对研究区干旱的监测、评估更具有优势。

In recent years,droughts have occurred frequently,which has severely affected the development of Xilin Gol League regional ecosystems and animal husbandry,and has posed a huge threat to regional economic development.Based on the monthly accumulated precipitation and monthly average temperature of 15 meteorological stations in the study area from 1980 to 2018,the SPI and SPEI were used to analyze the spatial and temporal characteristics of drought in Xilin Gol League,and the differences between SPI and SPEI in drought monitoring were compared.The results show that from 1980 to 2018,there were frequent persistent drought events in the Xilin Gol League,and the frequency and duration of continuous drought events showed an increasing trend as the years changed.The spatial distribution of drought frequency in the study area is always in a dynamic change.The frequency of droughts in the central-eastern and western regions is relatively high.The drought-prone areas gradually shift to the west,and the frequency of droughts gradually increases from east to west.With rise in temperature,the SPI’s ability to monitor regional droughts began to decline,especially for severe and extreme droughts.The SPEI has a strong ability to monitor abnormal droughts and is not easily affected by precipitation factors,which have more advantages for drought monitoring and evaluation.