Abstract: As one of the important factors affecting climate change by human activities, land use changes mainly affect climate system by changing the surface biogeophysical and biogeochemical processes. The impacts of land use change on climate system through biogeochemical processes have been extensively examined, but the understanding of biogeophysical processes is still insufficient, which is not conducive to accurate assessment of regional climate. This study focused on the Loess Plateau that has witnessed largescale and highintensity human activities. Based on the surface radiation energy data, the transfer of cropland from 2000 to 2015 was defined. The biogeophysical differences between cropland, forest, and grassland were quantified. Combined with the energy redistribution factor, the radiative and nonradiative effects of returning cropland to forest and grassland were estimated. Finally, we used the nonradiative forcing index (NRFI) to quantify the contribution of the nonradiative effect to the changes of land surface temperature. Our results showed that land use change caused 0.05 ℃ warming through the radiative effect and 0.21 ℃ cooling through the nonradiative effect on local surface temperature change. The nonradiative effect dominated responses of local temperature to land use change. During the study period, land surface temperature in the growing season dropped by 0.17 ℃ and the contribution of nonradiative effects was 69.7%. Surface temperature changes showed different sensitivity to energy redistribution factors, surface albedo, and soil heat flux. The energy redistribution factor dominated the land surface temperature change and reduced the surface temperature in the growing season by 0.21 ℃. Our results provide a theoretical basis for accurately assessing the influence of land use changes on regional climate and have implications for coping with or mitigating the impacts of climate change in the Loess Plateau.

Key words: Loess Plateau, land use change, land surface temperature, The Grain to Green Program, biophysical effect.