Arid Zone Research ›› 2023, Vol. 40 ›› Issue (7): 1040-1051.doi: 10.13866/j.azr.2023.07.02

• Weather and Climate • Previous Articles     Next Articles

Spatio-temporal variation of snow cover in Altai Mountains of Xinjiang in recent 20 years and its influencing factors

LI Hong1(),LI Zhongqin1,2,3(),CHEN Puchen1,PENG Jiajia3   

  1. 1. College of Geography and Environment Sciences, Northwest Normal University, Lanzhou 730070, Gansu, China
    2. State Key Laboratory of Cryospheric Science, Tianshan Glaciological Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China
    3. College of Science, Shihezi University, Shihezi 832003, Xinjiang, China
  • Received:2023-03-03 Revised:2023-05-19 Online:2023-07-15 Published:2023-08-01

Abstract:

Using MOD10A2 snow product data from 2001 to 2020, along with digital elevation and meteorological data, the spatiotemporal variation of snow cover in the Altai Mountains, Xinjiang, and the influence of topographic and meteorological factors over this period were analyzed. The results indicated the following. (1) Snow cover percentage (SCP) in the Altai Mountains of Xinjiang exhibited a decreasing overall trend from 2001 to 2020, with the lowest and highest values observed in 2007 and 2010, respectively, and a variation rate of -5.69%·(10a)-1. Troughs were observed throughout the year, with maximum and minimum troughs in January and July, respectively. Seasonally, SCP increased in fall and decreased in the other three seasons. The uneven distribution of climate conditions, including temperature and precipitation, caused fluctuations in the timing of maximum annual snow cover occurrence. The Altai annual SCP reached its peak between 96.45% and 99.92%, primarily observed in January and December. The lowest coverage range was 0.84%-2.27%, which occurred in July and August. (2) SCP showed a positive correlation with altitude, with lower SCP values below 500 m (average of 8.11%) and higher values above 2000 m (average of 99.08% in an area with stable snow cover all year round). SCP varied depending on the slope, with the northwest slope exhibiting the highest values (28.45%) and the south slope showing the lowest values (18.36%). (3) Land surface temperature exhibited higher and lower distributions in the northeast and southwest, respectively, and was significantly positively correlated with altitude. Moreover, 67.65% of the Altai Mountain region showed a downward trend in snow cover frequency (SCF) from 2001 to 2020. High mountain areas experienced increasing SCF, whereas plain and river areas exhibited decreasing SCF. (4) Temperature was the main factor influencing snow cover change, being negatively correlated with SCF over 9.08 × 103 km2 (80.52% of the total Altai Mountain 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 was positively correlated with 87.14% of regional SCF, with a weakened effect on SCF changes observed in high-altitude mountain areas and a more significant correlation observed in low-altitude areas.

Key words: snow cover, MOD10A2, spatial-temporal variation, meteorological factors, Altai Mountain of Xinjiang