UAV Oblique Imagery Reveals Order-of-Magnitude Changes in Snow Aerodynamic Roughness Length Under Shifting Meteorological Regimes at Qinling Station, East Antarctica

Snow aerodynamic roughness length ((Formula presented.)) plays a critical role in Antarctic surface energy and mass balance. Yet, (Formula presented.) is conventionally treated as a constant in turbulent flux calculations. Fine-scale spatiotemporal variations in (Formula presented.) remain largely unmonitored. This study employed multi-temporal uncrewed aerial vehicle oblique photogrammetry to construct digital surface models and estimate (Formula presented.) values for various underlying surfaces and weather conditions with the bulk-aerodynamic method at Qinling Station, East Antarctica. The results demonstrate similar spatial distribution patterns among five (Formula presented.) estimation models, yet reveal an order-of-magnitude discrepancy in absolute values. The (Formula presented.) values in snow sastrugi areas are approximately an order of magnitude lower than those in rock areas. Snow surface (Formula presented.) shows high sensitivity to changes in meteorological conditions. Snowfall results in an increase of the regional mean (Formula presented.) in the snow sastrugi area from 0.01 to 0.10 mm, while strong winds reduce it by approximately one order of magnitude. Furthermore, (Formula presented.) tends to increase with the spatial sampling scales. Fine-scale estimation of (Formula presented.) can be combined with wind-based (Formula presented.) observations to provide a basis for developing high-fidelity snow-atmosphere interaction models, which is particularly crucial for simulating complex polar climates and environments.