基于MODIS数据的西天山积雪时空分布特征研究

Temporal and Spatial Distribution of Snow Cover in the Western Tianshan Snow Based on the MODIS Data

摘要: 本文基于2001~2020年MODIS积雪产品，通过对积雪覆盖面积、积雪日数分析了西天山积雪的时空分布特征。结果表明：1) 年内积雪覆盖面积分布呈单峰型，1月份面积最大，7月份最少。西天山积雪覆盖面积呈略微减少趋势，主要体现在海拔1500~3000 m区域内。2) 春季和冬季的积雪覆盖面积明显减少，秋季略微增加，夏季变化不大。3) 西天山积雪日分布差异较大，最大年平均积雪日数为214 d，总积雪日主要集中在31~60 d，其比例约为西天山总面积的37.4%。4) 积雪日数为0d和91~120 d的所占面积比例无变化；积雪日数为31~60 d、≥121 d的呈减少趋势；积雪日数为1~30 d、31~60 d呈增加趋势。5) 20 a内西天山积雪日减少的面积占西天山总面积的52.9%，稳定区占46.9%，增加的区域只有0.18%。西天山积雪日数增加或减少的趋势是不明显的(P > 0.1)。

Abstract: Based on MODIS snow products from 2001 to 2020, through the snow cover area and the snow days, this paper analyses the space-time distribution features of the Western Tianshan snow. The results showed that: 1) Year distribution of snow cover area is unimodal type, and the biggest areas were in January and in July at least. The snow cover area in the Western Tianshan showed a slight decreasing trend, mainly in the area from 1500 m to 3000 m above sea level. 2) The snow cover area significantly reduced in winter and spring, increased slightly in autumn, and slightly changed in summer. 3) The distribution of snow cover days varies greatly in the Western Tianshan. The maximum average snow cover days is 214 days, and the total snow cover days are mainly concentrated in 31~60 days, accounting for 37.4% of the total area in the Western Tianshan. 4) The snow days 0 d and 91~120 d: no change of area ratio; Snow days in 31 to 60 d, 121 d showed a trend of decrease; Snow days in 1~30 d and 31 to 60 d showed a trend of increase. 5) During the past 20 years, the area with snow cover decreased 52.9%, the area with stable cover increased 46.9%, and the area with snow cover increased 0.18%. The increasing or decreasing trend of days with snow cover in Western Tianshan was not obvious (P > 0.1)