The Spatial Patterns and Trends of Sensible and Latent Heat Fluxes in the Northern Drought‐Prone Belt of China

The Northern Drought‐Prone Belt of China (NDPB), a characteristic ecotone between arid and humid climate regimes, experiences China's highest frequency of extreme drought events. This region exhibits a unique spatial coincidence with both the East Asian summer monsoon transition zone and a major ecological transition boundary. These overlapping transitional systems create pronounced gradients in precipitation, soil moisture, and leaf area index (LAI), which in turn drive distinct transitional patterns in latent (LHF) and sensible (SHF) heat fluxes. These gradient features demonstrate strong seasonal dynamics, reaching maximum intensity during summer season when summer monsoon amplifies the hydrothermal gradients of the underlying surface. Our analysis reveals divergent trends in surface energy fluxes across the NDPB. While LHF shows a significant increasing trend, SHF demonstrates a corresponding decrease. These changes occur despite decreasing trends in precipitation and soil moisture availability. This apparent paradox may be explained by the substantial vegetation growth (up to 20% increase) under global warming conditions. The expanded vegetation cover enhances biophysical regulation of surface processes. The intensified transpiration partially offsets the hydrological constraints imposed by reduced precipitation, maintaining elevated LHF levels even during soil moisture depletion. But the increased evapotranspiration exacerbates soil water losses, potentially amplifying drought vulnerability during periods of weakened monsoon circulation.