关键词: 土壤湿度, 华北, 暖季, GLDAS

Abstract:

The soil moisture data from observation over China were used to test the accuracy of assimilation data from GLDAS, results show that assimilated soil moisture can efficiently describe its spatial and temporal distribution and its variation over China in warm season, especially in North China, where the observation and GLDAS data are correlated significantly. As its efficiency, to study the characteristic of regional drought, GLDAS soil moisture data was used to access the long-term variation feature of soil moisture over North China in warm season in the period of 1948-2010, and also the impacts of temperature and precipitation on soil moisture were explored. Results show that soil moisture of all the four depth layers decreased similarly in the past 63 years and that of the middle two layers had aggravative decrease. The basic cyclic soil moisture was carried out by wavelet analysis and it concluded that for all the four depth layers, soil moisture had almost the consistent cycle with 3 years, 5 to 7 years and 15 years, and the 5 to 7 years cycle was the main cycle. For all the four layers, there was positive correlation between precipitation and soil moisture, but negative correlation between temperature and soil moisture, and the correlation with precipitation was weakened in the deeper soil layer while it was more obvious in the middle two layers with temperature.

Key words:  soil moisture, North China, warm season, GLDAS