内蒙古地区干旱时空变化特征及其对植被的影响

基于MODIS实际蒸散量(ET)和潜在蒸散量(PET)产品反演作物缺水指数(CWSI),采用多种统计方法研究干旱时空变化特征及其对植被生长的影响。结果表明:多年平均干旱程度由西南向东北逐渐递减,农作物主要以轻旱和中旱为主,草原主要以中旱和重旱为主,荒漠主要以重旱为主;除针叶林和沼泽外,其他植被类型旱情缓解;干旱年内变化特征呈双峰型曲线,且在Day113~Day144干旱最为严重,表现为重旱;各植被类型年内变化特征与全区变化趋势相一致,均呈双峰型曲线;夏旱对植被生长的胁迫作用最强,而年平均干旱强度对植被生长的胁迫作用主要由夏旱主导;春季灌丛、夏季和秋季农作物对干旱的响应较为敏感。研究结果可为内蒙古植物群落的生态预警和生态修复提供理论参考。

Temporal and Spatial Variation of Drought and Its Impact on Vegetation in Inner Mongolia

Inversion of Crop Water Stress Index (CWSI) was conducted based on the evapotranspiration (ET) and potential evapotranspiration (PET) of MODIS. Temporal and spatial variation of drought and its impact on vegetation were analyzed through a variety of statistical methods. The results showed that the annual average drought severity gradually decreased from southwest to northeast, the crops were mainly light and moderate drought, the grassland was mainly medium and heavy drought, and the desert was mainly severe drought. In addition, except coniferous forest and swamp, the drought tendency of other vegetation types was eased. The variation characteristics of annual drought showed a bimodal curve, and the severe drought occurred in 113 to 144 days. The annual variation characteristics of drought severity for each vegetation type were consistent with the change trend of the whole region, showing a bimodal curve. The impact of summer drought on vegetation growth was the strongest, and the stress effect of annual average drought intensity on vegetation growth was mainly dominated by summer drought. For different vegetation types, shrub in spring, crops in summer and autumn were more sensitive to drought. The results could provide theoretical reference for ecological early warning and ecological restoration of plant communities in Inner Mongolia.