关键词: 土壤湿度, 资料对比, 时空分布, 变化趋势

Abstract:

The applicability of five sets of widely-used soil moisture data (EAR-Interim, NCEP reanalysis data, GLADS assimilation data, CPC assimilation data and inversion data derived AMSR-E) was inspected by using the observation data over China during 1992-2012, and the spatial distribution and change tendency of soil moisture over China were analyzed. The results show that these five sets of moisture data could generally reflect distribution pattern of wet in the southeast and dry in the northwest and the tendency of soil moisture decreased from the southeast to the northwest, while soil in arid and semi-arid regions of northwest China was getting wetter and that in the Yangzi River region was getting drier. The CPC data was closest to the observational facts and it could better represent the local characteristics. The GLDAS and NCEP data had better correlation with observation data in seasonal variation and interannual variation, and they can reflect the time evolution characteristics of soil moisture. On this basis, the NCEP, CPC and GLDAS data which had better test effect were used to analyze the long-term trends of annual mean soil moisture, there was a relatively wet period from 1948 to 1996 and a relatively dry period from 1996 to 2012. The soil moisture became dry in the east and wet in the west, and the area becoming dry presented a dry zone from the northeast China, north China to the southwest China.

Key words: soil moisture, data intercomparison, temporal-spatial distribution, interannual variation