Test and Application of HCLDAS‐Based Temperature Data at Different Altitudes in the Hotan Area in Summer

ABSTRACT This study employed high‐resolution (1 × 1 km) multisource fusion data (HCLDAS) and observational data from 190 automatic weather stations to analyze summer temperature variations across 12 altitude levels in the Hotan area from June to August 2023. Statistical methods, including root mean square error (RMSE) and temperature accuracy rates (TT1, TT2), were applied to validate data reliability and investigate spatiotemporal patterns. Key findings include: (1) Data Validation: HCLDAS demonstrated high accuracy, with a mean RMSE of 0.42°C and temperature accuracies of 98.15% (≤ 1°C) and 99.08% (≤ 2°C), confirming its suitability for complex terrains. (2) Altitude‐Dependent Trends: High elevations (≥ 4500 m): Continuous warming from July to August (+0.37°C to +0.96°C), driven by glacier‐albedo feedback (e.g., Muztagh Ata retreat) and weakened westerlies enhancing thermal forcing, elevating the 0°C isotherm. Mid‐elevations (2000–4500 m): Sharp vertical cooling (−18.21°C total) but significant June–July warming (+1.24°C to +2.96°C). Low elevations: July–August cooling (−0.07°C to −1.05°C) due to cold air drainage and oasis effects (evaporation/dust reflection). (3) Diurnal Variability: Maximum daily temperature range (12.6°C) occurred at 1300–1500 m (arid landscapes), while the minimum (6.08°C) was observed at 4000–4500 m (rocky terrain). (4) Threshold Analysis: ≤ 0°C grids (38.51% of total) concentrated above 2500 m, while ≥ 35°C grids (55.59%) dominated below 3000 m, with cumulative hours increasing at lower altitudes. The results provide a scientific basis for high‐temperature monitoring, snowmelt flood warnings, and optimized meteorological infrastructure in arid, high‐altitude regions.