Spatiotemporal Patterns and Dominant Driving Factors of Sensible Heat Flux over the Mongolian Plateau During 1980–2025

The Mongolian Plateau is a critical region for land–atmosphere interactions in East Asia. Sensible heat flux (H), a key component of surface energy balance, significantly influences the Asian summer monsoon and atmospheric circulation. Using ERA5-Land reanalysis data (1980–2025), this study applies Empirical Orthogonal Function (EOF) and the Sequential Mann–Kendall test to diagnose the spatiotemporal patterns of H over the Mongolian Plateau and its dominant driving factors. Results indicate that H over the Mongolian Plateau exhibits a distinct spatial pattern, with higher in the west and south and lower in the east and north. With 105° E as the dividing line, the mean flux is 31.5 W m−2 in the western region and 25.0 W m−2 in the eastern region; with 46° N as the boundary, the corresponding values are 32.2 W m−2 in the south and 23.1 W m−2 in the north (reanalysis-relative, not observation-validated absolute values). EOF analysis identifies that the first mode captures the east–west gradient, while the second and third modes reflect opposing interannual thermal variations in zonal and meridional directions, respectively. Together, these three modes account for more than half of the total variance in surface thermal anomalies. Seasonally, H peaks in summer (46.8 W m−2), followed by spring (42.8 W m−2) and autumn (17.4 W m−2), and reaches its minimum in winter (3.9 W m−2). Over the 1980–2025 period, the annual mean H presents a statistically significant increasing trend of 0.068 W m−2 yr−1. Attribution analysis further reveals that the surface–air temperature difference dominates the spatiotemporal variations, whereas wind speed plays a comparatively minor role. These findings provide a scientific foundation for understanding ecological and environmental evolution on the Mongolian Plateau in the context of climate change.