Biophysical feedback of forest canopy height on land surface temperature over contiguous United States
Abstract Forests are considered important to the mitigation of climate change. Biophysical effects of afforestation and deforestation on land surface temperature (LST) have been extensively documented. As a fundamental variable of forest structure, however, few studies have investigated the biophysical feedback of forest canopy height changes on LST at large scale. This study is designed to investigate the impact of forest canopy height changes on local land LST and clarify the biophysical processes controlling LST change from 2003 to 2005 over contiguous United States (CONUS) based on satellite observations. To this end, one satellite-based forest canopy height product is selected, and space-for-time approach together with energy balance equation is applied. Results show that for different forest types, namely evergreen forest (EF), deciduous forest (DF), and mixed forest (MF), taller forests present a net cooling effect (0.056 to 0.448 K) than shorter forests at annual scale. The increase in net radiation and sensible heat flux was less than the increase in the latent heat flux when forest canopy height classes converting from shorter to taller, resulting in annual net cooling effects. Furthermore, the cooling effect of EF is stronger than DF and MF, whether for tall, medium, or short forest canopy height classes. Multiple regression analysis reveals that the changes in biophysical components can effectively explain the LST change during growing season. Our findings provide a new insight for forest management decision in the purpose of mitigating climate warming.