Inclusion of land use changes in long-term regional climate simulations over East Asia

Long-term simulations with regional climate models (RCMs) show biases over East Asia that result partly from fix-in-time land use data (EX2001). Using four satellite-based land use images (EX8901) from the past 30 years instead of default values, 34-year integrations were performed to make comparisons (EX8901 minus EX2001) over East Asian land areas. The decreased albedo (-0.019) resulted in weakened upward short-wave flux, contributing to positive surface radiative forcing (2.89Wm(-2)), which then induced enhanced sensible heat fluxes. The near-surface wind speed was weakened (-0.15ms(-1)) in relation to the increased roughness length (0.042 m) and weakened pressure gradient, and induced a decreased precipitation bias of 0.0095mmday(-1). The increased ground temperature and enhanced soil water content promoted strengthened sensible and latent heat fluxes, which induced a decreased surface air temperature bias (-0.24 degrees C). Results show that by including land use changes, model simulations can be improved.