Drought has a deep impact in Inner Mongolia, which relies on livestock and farming. The temporal and spatial variability of drought conditions in Inner Mongolia were analyzed with a drought severity index (DSI), which is derived from the ratio of evapotranspiration to potential evapotranspiration and the normalized difference vegetation index (NDVI), as measured by remote sensing. Soil moisture as an important drought measure has not been used in the calculation of DSI. Using monthly DSI data during the growing season (May–September) in 2001–2010, the relationship between DSI and soil moisture was investigated with correlation coefficient and regression analysis. Different seasonal and spatial patterns of drought occurrence were found in the notable drought years of 2001, 2007, and 2009. The largest correlations between DSI and soil moisture were attributed to the links between evapotranspiration and soil moisture. The spatial distribution of the correlation coefficients between DSI and soil moisture varied seasonally, tracking closely with the movement of rainfall belt. DSI could not reflect the variation of soil moisture in woodland. In grassland, DSI correlated with surface soil moisture in the east in the beginning of the growing season. As the rainfall belt expands to the west in the second half of the growing season, DSI reflected apparently deeper soil moisture conditions because of the spatial difference of soil properties, i.e., the water-holding capacity becomes larger from west to east.

干旱对依靠畜牧业和农业生产的内蒙古造成了深远的影响。使用干旱严重度指数（DSI）分析了内蒙古干旱状况的时空变化，该指数是通过遥感测量得出的蒸散量与潜在蒸散量之比和归一化植被指数（NDVI）得出的。在DSI的计算中尚未使用土壤水分作为重要的干旱措施。使用2001-2010年生长季（5月至9月）的DSI每月数据，通过相关系数和回归分析研究了DSI与土壤水分之间的关​​系。在2001、2007和2009年明显的干旱年份，发现了不同的干旱发生季节和空间格局。DSI与土壤水分之间最大的相关性归因于蒸散与土壤水分之间的联系。DSI与土壤水分之间相关系数的空间分布随季节变化，与降雨带的运动密切相关。DSI不能反映林地土壤水分的变化。在草地上，DSI与生长季节开始时东部的表层土壤水分相关。随着降雨带在生长季节的后半期向西扩展，DSI反映出土壤水分状况明显更深，这是由于土壤性质的空间差异，即持水能力从西向东变大了。DSI与土壤水分之间相关系数的空间分布随季节变化，与降雨带的运动密切相关。DSI不能反映林地土壤水分的变化。在草地上，DSI与生长季节开始时东部的表层土壤水分相关。随着降雨带在生长季节的后半期向西扩展，DSI反映出土壤水分状况明显更深，这是由于土壤性质的空间差异，即持水能力从西向东变大了。DSI与土壤水分之间相关系数的空间分布随季节变化，与降雨带的运动密切相关。DSI不能反映林地土壤水分的变化。在草地上，DSI与生长季节开始时东部的表层土壤水分相关。随着降雨带在生长季节的后半期向西扩展，DSI反映出土壤水分状况明显更深，这是由于土壤性质的空间差异，即持水能力从西向东变大了。