Biogeophysical Forcing of Land-Use Changes on Local Temperatures across Different Climate Regimes in China

摘要

Land-use changes (LUCs) strongly influence regional climates through both the biogeochemical and biogeophysical processes. However, many studies have ignored the biogeophysical processes, which in some cases can offset the biogeochemical impacts. We integrated the field observations, satellite-retrieved data, and a conceptual land surface energy balance model to provide new evidence to fill our knowledge gap concerning how regional warming or cooling is affected by the three main types of LUCs (afforestation, cropland expansion, and urbanization) in different climate zones of China. According to our analyses, similar LUCs presented varied, even reverse, biogeophysical forcing on local temperatures across different climate regimes. Afforestation in arid and semiarid regions has caused increased net radiation that has typically outweighed increased latent evapotranspiration, thus warming has been the net biogeophysical effect. However, it has resulted in cooling in subtropical zones because the increase in net radiation has been exceeded by the increase in latent evapotranspiration. Cropland expansion has decreased the net radiation more than latent evapotranspiration, which has resulted in biogeophysical cooling in arid and semiarid regions. Conversely, it has caused warming in subtropical zones as a result of increases in net radiation and decreases in latent evapotranspiration. In all climatic regions, the net biogeophysical effects of urbanization have generally resulted in more or less warming because urbanization has led to smaller net radiation decreases than latent evapotranspiration. This study reinforces the need to adjust land-use policies to consider biogeophysical effects across different climate regimes and to adapt to and mitigate climate change.