常用气象干旱指数SPEI和SPI在陕北地区的适用性研究

Adaptability research on the common meteorological drought indexes of SPEI and SPI in the northern Shaanxi province

基于1981—2012年陕北地区10个站点的气象数据,利用标准化降水蒸腾指数(SPEI)和标准化降水指数(SPI)2个常用的气象干旱指数开展干旱时空分布及典型干旱事件识别研究,并利用旱灾历史记录进行验证,评价2种干旱指数在陕北地区的适应性。结果表明,在年尺度上,SPEI较SPI更能准确地描述陕北地区干旱的年际变化,其发现陕北地区近32年来干旱呈加剧态势;在季节尺度上,2种干旱指数的表述基本一致,均发现陕北地区以春旱为主;从空间分布上看,二者均发现陕北东南部是特旱高发区;在28次典型干旱事件的识别中,SPEI识别出19次,SPI识别出6次,SPEI较SPI更为准确。综合来看,SPEI更适用于陕北地区的干旱监测。

Based on the meteorological data of 10 stations in northern Shaanxi province from 1981 to 2012,the temporal and spatial distribution of drought and the identification of typical drought events were studied by using two commonly used meteorological drought indexes of SPEI and SPI,and the drought historical records were used to verify the adaptability of the two drought indexes in northern Shaanxi province.The results showed that,on the annual scale,SPEI could more accurately describe the interannual variation of drought in northern Shaanxi province than SPI.It was found that the drought in northern Shaanxi province has intensified in the past 32 years.On the seasonal scale,the expressions of the two drought indexes were basically the same,and it was found that spring drought was the main drought in northern Shaanxi province.From the point of view of spatial distribution,both of them found that the southeast of northern Shaanxi province was a region with high incidence of extreme drought.In the identification of 28 typical drought events,19 events were identified by SPEI and 6 events identified by SPI,and SPEI was more accurate than SPI.To sum up,SPEI is more suit⁃able for drought monitoring in northern Shaanxi province.