Spatio-temporal distribution and influencing factors of soil moisture content in Henan Province during 1948—2021

This study constructed a monthly soil moisture content dataset of Henan Province during 1948—2021 by combining 1948—2014 GLDAS_2.0 data and 2000—2021 GLDAS_2.1 data. Through the Mann-Kendall (M-K) trend analysis, mutation test, wavelet analysis, and cross-correlation analysis, this study revealed the spatio-temporal distribution and critical influencing factors of soil moisture content in Henan Province. The results show that compared with the monthly soil moisture content data provided by GLDAS_2.1, the reconstructed monthly soil moisture content data during 2000—2014 showed an average deviation, average absolute error, and root mean square error of 2.09 mm, 13.01 mm, and 18.26 mm, respectively, indicating reliable data. According to the constructed soil moisture content data, the soil moisture content decreased at a rate of 0.301 0 mm/a during 1948—2021, with change rates of -0.236 8 mm/a in spring, -0.085 5 mm/a in summer, -0.380 5 mm/a in autumn, and -0.240 3 mm/a in winter in Henan Province. Spatially, the soil moisture content decreased from south to north, highly consistent with precipitation and evapotranspiration. The soil moisture content was 2.63 mm/cm in the vertical direction. The wavelet and cross-correlation analyses show that precipitation is a critical factor influencing soil moisture content. This study revealed the long-time-series spatio-temporal distribution of soil moisture content in Henan Province, providing a basis for the scientific management of surface water resources in Henan Province.