Regional Characteristics of Soil Moisture Evolution in Northern China over Recent 50 Years
GUO Weidong 1 , MA Zhuguo 1 , YAO Yonghong 2 (1. Chinese Academy of Sciences Key Laboratory of Regional Climate-Environment Research for Temperate East Asia,START Regional Center for East Asia,Institute of Atmospheric Physics, CAS, Beijing100029, China;2. Department of Atmospheric Sciences, Nanjing University, Nanjing210093, China)
Regional characteristics of soil moisture evolution in northern China are analyzed based on the monthly retrieved soil moisture data of 139 stations from 1951 to 1999. The results show that evolution of soil moisture at different levels coincides with each other very well. North China experienced a wet period during the late 1960s to late 1970s. An abrupt change occurred at the end of the 1970s and the soil moisture began to decrease. The descending trend of soil moisture in North China is especially evident in the late 1990s. For Northeast China, the 1970s is a distinct dry period. In terms of seasonal trend, however, no apparent decrease of soil moisture has been found since 1980 in North China. In addition, a notable phenomenon is the general decrease of soil moisture in autumn over wide regions of northern China, especially in Northeast China.