近20 a 新疆阿尔泰山积雪时空变化及其影响因素

Using MOD10A2 snow product data from 2001 to 2020, along with digital elevation andmeteorological data, the spatiotemporal variation of snow cover in the Altai Mountains, Xinjiang, and theinfluence of topographic and meteorological factors over this period were analyzed. The results indicated thefollowing. (1) Snow cover percentage (SCP) in the Altai Mountains of Xinjiang exhibited a decreasing overalltrend from 2001 to 2020, with the lowest and highest values observed in 2007 and 2010, respectively, and avariation rate of ? 5.69%·(10a) ? 1. Troughs were observed throughout the year, with maximum and minimumtroughs in January and July, respectively. Seasonally, SCP increased in fall and decreased in the other threeseasons. The uneven distribution of climate conditions, including temperature and precipitation, causedfluctuations in the timing of maximum annual snow cover occurrence. The Altai annual SCP reached its peakbetween 96.45% and 99.92%, primarily observed in January and December. The lowest coverage range was0.84%-2.27%, which occurred in July and August. (2) SCP showed a positive correlation with altitude, withlower SCP values below 500 m (average of 8.11%) and higher values above 2000 m (average of 99.08% in anarea with stable snow cover all year round). SCP varied depending on the slope, with the northwest slopeexhibiting the highest values (28.45%) and the south slope showing the lowest values (18.36%). (3) Land surfacetemperature exhibited higher and lower distributions in the northeast and southwest, respectively, and wassignificantly positively correlated with altitude. Moreover, 67.65% of the Altai Mountain region showed adownward trend in snow cover frequency (SCF) from 2001 to 2020. High mountain areas experienced increasingSCF, whereas plain and river areas exhibited decreasing SCF. (4) Temperature was the main factor influencingsnow cover change, being negatively correlated with SCF over 9.08 × 103 km2 (80.52% of the total AltaiMountain area). Therefore, as altitude increases, the impact of temperature on snow cover gradually diminishes.Annual average precipitation in Altai decreased gradually from northwest to southeast, and precipitation waspositively correlated with 87.14% of regional SCF, with a weakened effect on SCF changes observed in highaltitudemountain areas and a more significant correlation observed in low-altitude areas.