Biophysical effects of croplands on land surface temperature

Area of Science:

• Earth System Science
• Climate Science
• Agricultural Science

Background:

• Land use change, specifically converting natural vegetation to croplands, significantly impacts local land surface energy budgets.
• Understanding these impacts is crucial for assessing regional climate dynamics and developing sustainable land management practices.

Purpose of the Study:

• To analyze the biophysical mechanisms through which croplands influence daily mean land surface temperature (LST).
• To quantify the global patterns of cropland-induced LST changes and identify key influencing factors.

Main Methods:

• Utilized two decades of satellite data to observe land surface changes.
• Employed a physics-based framework to analyze the biophysical drivers of LST variations.
• Investigated the roles of aerodynamic resistance, latent heat flux, and leaf area index.

Main Results:

• Globally, 60% of croplands exhibit an annual warming effect, while 40% show a cooling effect compared to surrounding natural ecosystems.
• Aerodynamic resistance was identified as the dominant factor influencing LST by modulating latent heat flux.
• LST change magnitude is negatively correlated with the difference in leaf area index between croplands and surrounding biomes.

Conclusions:

• Cropland expansion leads to complex, regionally varied LST changes, with strongest warming in temperate dry regions and less disturbance in hot, wet regions.
• Findings underscore the intricate relationship between land use, vegetation characteristics, and regional climate patterns.
• Provides critical insights for sustainable agriculture and land-based climate change mitigation strategies.