ZHAO Shuixia, ZHOU Quancheng, WANG Wenjun, WU Yingjie

Abstract: Exploring the dry and wet patterns of climate and its evolution trend in Inner Mongolia is of great significance to monitoring and preventing drought and flood disasters. The monthly average precipitations from 1970 to 2020 of 45 meteorological stations in Inner Mongolia were used in this study. The dry-wet climate characteristics and periodic evolution trend of Inner Mongolia under multi-time scales were explored by using a standardized precipitation index(SPI). The linear tendency, mutation test, and Morlet wavelet analysis methods have also been used in this study. Results show that during 1970-2020, the drought intensity in Inner Mongolia was mainly light and moderate droughts, and local and large scale droughts have frequently occurred. The drought tendency in summer is significant, which is significantly greater than the inter-annual drought level. In terms of the dry-wet spatial distribution in different ecological functional areas, the drought in the northeast forest and western desert areas have been alleviated, and in the middle steppe has aggravated. The drought impact range and drought intensity in typical steppe areas are significant, which is a high-risk area of drought. The wavelet analysis shows that the dry-wet climate appeares alternately in Inner Mongolia. The dry-wet climate in Inner Mongolia has a short period of 11 years and a long period of 49 years, the short period coincides with the sunspot activity period, and the long period reveals that the region is in a humidification period.

Keywords: standardized precipitation index, dry-wet climate characteristics, Inner Mongolia, wavelet analysis, drought and flood disaster