Spatial and Temporal Variations of Drought in Inner Mongolia, China

Drought has become an important natural disaster, affecting the development of Inner Mongolia, as an important animal husbandry region in China. In this study, the characteristics and trends of the Inner Mongolia drought are thoroughly analysed by calculating the standardised precipitation evapotranspiration index (SPEI) at different time scales, based on monthly precipitation and temperature data from 40 national meteorological stations in Inner Mongolia from 1958 to 2019. Subsequently, the area drought intensity (ADI), which is a comprehensive evaluation indicator for evaluating drought intensity within the region, is proposed, taking into account the effects of the persistent drought on drought intensity. The results show that drought has increased during this period, with a remarkable increase in the frequency and the area of drought. The areas with stronger drought intensity are mainly located in the west, north central, and the western area of the east. Since 2000, March to October are identified as drought-prone months and April is characterised as the month with the highest frequency of drought. The inflection points of SPEI and climate conditions both appeared in 1990s and it is speculated that the increase in drought may have been caused by excessive temperature rise. The frequency, coverage area, and continuous duration of drought have increased greatly after climate mutation in this region. According to the changes in the spatial distribution of the ADI and frequency of drought occurrence, the drought-stricken areas shifted from the southeast to the northwest after climate mutations. The findings from this study provide a theoretical basis for the drought management of Inner Mongolia.