Analysis on the Thermal Environment Effects and Their Biophysical Factors of Agricultural Lands in Humid Subtropical Regions

To analyze the influence of agricultural land in subtropical humid zone on regional climate, the spatial and temporal variation characteristics of the thermal environmental effect of agricultural land in subtropical humid zone and its relationship with the main biophysical factors were analyzed in Jiangxi Province, based on MODIS surface temperature data from 2003 to 2019, with natural forest land as a reference. Results show: (1) agricultural lands warm the land surface significantly relativity to natural forests during the day, with annual mean temperature increase of 1.9 ℃, whereas cool the temperature substantially at night; (2) the thermal environment effects of agricultural lands vary greatly by the season, especially at night, characterized by weak nighttime warming effects du-ring summer; (3) both the daytime warming and nighttime cooling effects of agricultural lands show upward trends from 2003 to 2019; (4) the thermal environment effects of agricultural lands are primarily controlled by evapotranspiration during the day and by the joint control of evapotranspiration and surface albedo at night.