Infrared Land Surface Emissivity Dynamics in the Taklimakan Desert : Spatiotemporal Patterns and Key Drivers

This investigation systematically quantifies the spatiotemporal patterns and governing mechanisms of land surface emissivity (LSE) across three infrared wavelengths (8.3, 8.6, and 9.1 µm) in the hyper-arid Taklimakan Desert using 23-year satellite records (2001–2023). Our analysis reveals several key findings: (1) Despite theoretical sensitivity to soil moisture, LSE exhibits a paradoxical decadal increase (0.12 ± 0.03 decade⁻¹) concurrent with regional drying (-0.15 g/kg decade⁻¹), demonstrating thermal processes dominate 68 ± 7% of variability through particle expansion/contraction cycles; (2) Surface temperature exerts independent control, reducing emissivity by 0.0029 ± 0.0012 per 1°C, with maximum sensitivity at 9.1 µm (-0.0035 ± 0.0015); (3) Spectral analysis identifies wavelength-specific responses—the 8.6 µm band displays highest interannual stability (CV = 1.1 ± 0.3%), while 8.3 µm shows greatest surface sensitivity (CV = 2.9 ± 0.5%), with summer peaks (0.89 ± 0.02) amplified by aeolian processes in central dunes (ΔLSE > 0.07). These findings redefine LSE controls in hyper-arid environments through thermal-aeolian coupling mechanisms, providing critical constraints for desertification-climate feedback models.