Comparative Analysis of Various Soil Moisture Datain Sichuan Province

From two aspects of precipitation response and index evaluation,comparative analyzing soil moisture data of CLDAS products,manual soil moisture observation and automatic soil moisture stations from 2017 to 2018 at Xichang,Yibin and Lezhi in Sichuan Province.The results show that the soil relative humidity of three kinds of data has better response to precipitation impact.Among them,the response of automatic station to soil moisture change is the most obvious,while the response of CLDAS is gentle.The response of CLDAS volume water content to precipitation impact is not as good as CLDAS relative humidity,especially in the deep layer,which basically does not respond to precipitation impact.The comparative evaluation indicators show that the COR of soil relative humidity between the manual observation and the automatic stations is the best,the COR between two of three kinds of data at Xichang is larger than that of the other two stations,the correlation between two of three kinds of data at Lezhi is poor,and the BIAS and RMSE are also large.The COR between two of three kinds of data of each station of volumetric water content is less than that of relative humidity.Overall,the response of CLDAS soil moisture products,especially relative humidity,to precipitation in shallow layer is better than that in deep layer,and the correlation with manual observation and automatic stations is better than that in deep layer.The products of CLDAS soil humidity in shallow layer can make up for the sparse defects of automatic stations in some areas of Sichuan.