%0 Journal Article %A LI Liang %A YANG Zesu %A HE Hang %T Evapotranspiration-precipitation coupling strength response to hydrothermal factors over northern China %D 2022 %R 10.11755/j.issn.1006-7639(2022)-05-0791 %J Journal of Arid Meteorology %P 791-803 %V 40 %N 5 %X

As a land-atmosphere coupling “hot spot”, the northern China climate transition zone has a sharp spatial gradient of hydrothermal conditions, which plays an essential role in shaping the spatial and temporal pattern of evapotranspiration-precipitation coupling, but which mechanisms still remain unclear. Based on multi-source fusion of evapotranspiration, precipitation, temperature and satellite remote sensing soil moisture data, this study analyzes the spatial and temporal variation in evapotranspiration-precipitation coupling strength in the climate transitional zone of northern China and its relationship with soil moisture and air temperature. Results show that evapotranspiration-precipitation coupling strength gradually transitions from strong positive in the northwest to negative in the southeast and northeast corners. The evapotranspiration-precipitation coupling gradually increases with the decrease of spatial soil moisture and enhances with the increase of evapotranspiration variability. When considering the synergistic effect of water and heat, the synergistic effect of soil moisture and mean temperature is more influential than the synergistic effect of soil moisture and temperature variability on the spatial distribution of evapotranspiration-precipitation coupling strength, and plays a dominant role. Temporally, the coupling strength showed a intra-annual variation in the order of weakening in spring, summer, autumn and winter, and was characterized by obvious inter-annual fluctuations. Soil moisture variability and mean temperature are the main factors dominating the intra-annual variation of evapotranspiration-precipitation coupling in northern regions, and the mean soil moisture and soil moisture variability have significant effects on the inter-annual variation of evapotranspiration-precipitation coupling. When considering the synergistic effect, the intra-annual cycle of mean moisture and temperature jointly determines the intra-annual variation of evapotranspiration-precipitation coupling; and their effects on the inter-annual variation of evapotranspiration-precipitation coupling are significant only in the semi-arid region where the coupling is the largest. The results of the study can improve the understanding of the response of land-atmosphere coupling strength to the spatial and temporal changes of land surface state and provide a reference for improving the numerical simulation of land-atmosphere coupling.

%U http://www.ghqx.org.cn/EN/10.11755/j.issn.1006-7639(2022)-05-0791