Variation in the surface radiation budget over different land covers in a subtropical humid region: evidence from ground observations

The surface radiation is a crucial variable for understanding global climate and eco-environment change, which exhibits significant variations over time and space. In this study, we used in situ ground observations to estimate variations of the surface radiation budget over grassland and urban areas in a subtropical humid region. Our results revealed a positive radiation budget that varied over different land covers. Specifically, grassland exhibited a higher shortwave radiation, while urban area was characterized by the higher longwave radiation. Notably, the surface radiation budget (Rn) was much greater in grassland (77.60 W-2/m) than that in urban area (61.93 W-2/m), which was mainly attributed to the difference in longwave radiation. Additionally, the atmospheric pressure showed a strong correlation with the radiations, while precipitation and relative humidity presented relatively weak correlations. Furthermore, the correlations with climate were stronger in grassland than that in urban areas, suggesting complex interactions with anthropogenic factors during the process of urbanization. Results of this study would help reveal the characteristics and corresponding mechanisms of surface radiation budgets, which would support climatic adaptation and ecology management.

Automated summary

This study used ground observations to estimate the variations of surface radiation budget in grassland and urban areas in a subtropical humid region. The results showed that grassland had higher shortwave radiation, while urban areas had higher longwave radiation. The surface radiation budget was higher in grassland compared to urban areas, mainly due to the difference in longwave radiation. Atmospheric pressure showed a strong correlation with radiation, while precipitation and relative humidity had relatively weak correlations. The correlations with climate were stronger in grassland than in urban areas, indicating complex interactions with anthropogenic factors during urbanization. The results of this study can help understand the characteristics and mechanisms of surface radiation budgets and support climate adaptation and ecological management.