ZHOU Yanga, LI Ninga, JI Zhong-huia, GU Xiao-tiana, FAN Bi-hang
JOURNAL OF NATURAL RESOURCE
drought; standard precipitation index (SPI); Inner Mongolia region
The evolution characteristics of the annual and seasonal frequency, intensity and coverage of drought in the Inner Mongolia region for the past 30 years were analyzed based on the standardized precipitation index (SPI) as a drought index with the data of monthly precipitation of 47 ground meteorological stations during the period from 1981 to 2010. The drought coverage is defined as a ratio that the number of drought occurrence stations occupies the total observed stations. Results show that the trends of the annual, fall and winter drought intensity were not obvious over the past 30 years, while the trends in spring and summer increased significantly. The drought intensity at the annual and seasonal scales exhibited a mild level over the past 30 years. The drought coverage appeared as the features of the local and regional drought at the seasonal and annual scales. The northeastern Inner Mongolia, Hulunbeier, is a region where the annual drought, moderate, heavy and severe drought are all most likely to occur, and should pay special attention to it in order to reduce the damage, while the frequency of drought occurrence in the western Alashan League is relatively low. From the perspective of seasonal scale, the frequency of drought occurrence in spring and winter demonstrated consistency, including the level of moderate, heavy and severe drought. That is, the frequency of drought occurrence in the western and southeastern inner Mongolia was low, while the eastern, central, and northern parts were relatively high. These findings provide valuable insights into the drought monitoring, early warning and drought disaster mitigation project in the context of global climate change.