Responses of spring soil moisture of different land use types to snow cover in Northeast China under climate change background

Abstract

To explore the impact of climate change on snow cover and spring soil moisture (SM) in areas with seasonally frozen soil, snow cover parameters and spring SM for different land use types in Northeast China are extracted based on remote sensing snow cover and SM products. Snow cover parameters include snow days (SD), first day of snow cover (FSD), last day of snow cover (LSD), maximum snow depth (MSD) and average snow depth (ASD). The spatiotemporal variations and correlations between snow cover parameters and spring SM for different land use types are analyzed. The results showed that the average spring SM for different land use types was ordered woodland > farmland > grassland, with obvious woodland and farmland increases. Woodlands had many SD and large snow depths (MSD and ASD) that eventually decreased. Farmland SM increased significantly in spring, which aided crop development. The decrease in grassland spring SM was not obvious, but the snow cover parameters of certain areas decreased notably. Snow cover significantly impacted farmland SM, and correlation coefficients were highest between all snow cover parameters and SM in spring. The correlations between grassland snow cover parameters and SM in April were higher than those in May, but woodland snow cover parameters and spring SM were not correlated. Among the five snow parameters, FSD had the lowest correlation with spring SM, and SD had the greatest impact on SM. These results show the significant relationship between snow cover and SM and reveal relevant patterns. As future climate warming may introduce drought risk to woodland and grassland areas, advance preparations should be made. Farmland areas will continue to maintain appropriate SM, which is beneficial for agricultural development.