基于生态分区的1980-2015年内蒙古干旱动态

Dynamic of the Drought Based on the Ecological Partition in Inner Mongolia During 1980-2015

为研究内蒙古干旱时空分布特征,将内蒙古地区分为荒漠生态分区、草原生态分区和森林生态分区,选用标准化降水指数为气象干旱评价因子,对1980—2015年内蒙古降水数据进行了动态分析。结果表明:(1) 1980—2015年,内蒙古草原和森林区的SPI12有轻微减小趋势,而荒漠区的SPI12有增加趋势。(2)荒漠区干旱强度主要为中旱和轻旱,草原区以轻旱为主,森林区发生不明显干旱、轻旱和中旱的频率一样。荒漠和草原区干旱影响范围主要为无明显干旱和全域性干旱,而森林区主要为无明显干旱和区域性干旱。(3)春季3个区的SPI都有明显增加趋势。夏季3个区的SPI均有减小趋势。秋季荒漠区的SPI有增加趋势,草原区变化趋势不明显,而森林区SPI有减小趋势。冬季森林和草原区的SPI有增大趋势,而荒漠区SPI无明显变化趋势。(4)春季3个区多数站点的SPI值均有增加趋势。夏季3个区多数站点的SPI值都呈减小趋势。内蒙古秋季SPI变化趋势率表现为西部地区增大,东部地区减小。冬季荒漠生态分区SPI有增加趋势的站点多数分布于西部,有减小趋势的站点多分布于东部,草原区SPI有增大趋势的站点数较多,森林区的全部站点的SPI值都有增大的趋势。研究结论可为内蒙古地区干旱的监测预警和防灾减灾提供理论依据。

In order to study the spatial and temporal distribution characteristics of drought in Inner Mongolia, Inner Mongolia region is divided into desert ecological zones, grassland ecological partitions and forest ecological zones. Using standardized precipitation index as meteorological drought evaluation factor, the precipitation data of Inner Mongolia from 1980 to 2015 were analyzed. The results showed that:(1) from 1980 to 2015, SPI12 in grassland and forest areas showed a slight decreasing trend, while SPI12 in desert areas of Inner Mongolia showed an increasing trend;(2) the drought intensity in the desert areas was mainly moderate drought and light drought, while it was mainly light drought in the glassland areas;the frequency of non-obvious drought, light drought and moderate drought in forest areas were the same;the drought scope in desert and grassland areas was mainly affected by no obvious drought and regional drought, while the drought scope in forest areas was mainly affected by no obvious drought and regional drought;(3) SPI in all three regions showed a significant increase trend in spring;SPI decreased in all three regions in summer;SPI in desert areas tended to increase in autumn, and the change trend of SPI in grassland areas is not obvious,while SPI in forest areas tended to decrease;in winter, SPI in forest and grassland areas tended to increase, while SPI in desert areas showed no obvious trend;(4) SPI values of most sites in the three regions showed an increasing trend in spring;SPI values at most sites in the three regions showed a decreasing trend in summer;the trend rate of SPI change in Inner Mongolia in autumn was increasing in the west and decreasing in the east;most of the sites with increasing tend of SPI in desert ecosystem area in winter were distributed in the west, and the stations with decreasing trend mostly distributed in the east, there are more sites with increasing trend of SPI in grassland area, and the SPI values of all sites in the forest area had an increasing trend. The results can provide theoretical basis for drought monitoring, early warning, and disaster prevention and reduction in Inner Mongolia.