Biophysical effects of croplands on land surface temperature
Chi Chen, Yang Li, Xuhui Wang, Xiangzhong Luo, Yue Li, Yu Cheng, Zhe Zhu
Abstract
Converting natural vegetation to croplands alters the local land surface energy budget. Here, we use two decades of satellite data and a physics-based framework to analyse the biophysical mechanisms by which croplands influence daily mean land surface temperature (LST). Globally, 60% of croplands exhibit an annual warming effect, while 40% have a cooling effect compared to their surrounding natural ecosystems. Aerodynamic resistance is identified as the dominant biophysical factor impacting LST by adjusting latent heat flux. The magnitude of cropland-induced LST change is negatively correlated with the difference in leaf area index between croplands and their surrounding biome types. The strongest warming occurs in temperate dry regions where croplands are surrounded by savannas. However, a lower-than-expected LST disturbance is seen in hot and wet regions where croplands are surrounded by rainforests, attributed to lower cropland fraction and energy limitations. These findings highlight the complex interplay of land use, vegetation, and regional climate, providing valuable insights into sustainable agriculture and land-based climate change mitigation. Croplands alter land surface temperature, with 60% warming and 40% cooling effects globally. Temperature changes are driven by convection, which is influenced by leaf area index differences. The warming is strongest in temperate dry regions surrounded by trees.