基于MODIS积雪覆盖产品的中国天山积雪时空分布特征研究

利用2002-2016年MODIS逐日积雪遥感产品(MOD10A1、MYD10A1),采用日产品合成法、临近日分析法、空间滤波法和相邻时间合成法,生成天山山区逐日晴空积雪遥感产品数据集,研究分析了天山山区积雪时空分布特征。结果表明：近15a,天山山区平均积雪覆盖面积变化不明显,呈略微减少趋势,但主要表现为年际间的波动变化；分季节来看,天山山区积雪覆盖面积冬季 > 秋季> 春季 > 夏季；积雪面积从9月开始积累,1月达到峰值,占天山总面积的50±25%,3月开始消融,8月达到最低值,仅占天山总面积的为3.5±2%。；天山山区大部分区域积雪开始时间在第300天之后,积雪结束时间在第40~150天左右,海拔较高的区域积雪开始时间较早；天山山区平均积雪日数小于60天的不稳定积雪区主要分布在天山南坡、北坡边缘地带,占整个天山面积的44.57%,平均积雪日数在60~300天之间的区域占比为53.4%,主要分布在天山中部和北坡部分区域,平均积雪日数大于300天的永久积雪区,主要分布在海拔3800以上区域,占天山面积的2.03%。

A Study on Temporal and Spatial Distribution of Snow Cover in Tianshan Mountains of China Based on Daily Cloudless Snow Cover Product

The use of remote sensing products 2002-2016 MODIS daily snow (MOD10A1, MYD10A1),combining the existed cloud removal methods,based on daily snow products synthesis, near day analysis,temporal filter method and spatial filter method,with which the 15-year-long daily snow cover product in clear air of Tianshan area from2002 to 2016 was generated.Then investigated the temporal and spatial distribution characteristics of snow cover in Tianshan Mountains. It is found that the average snow cover area in Tianshan Mountains changed little in the recent 15 years, and there is a slight decrease trend, mainly as interannual fluctuation. For season,the snow cover area of Tianshan mountain in winter > autumn > spring > summer; Snow area began to accumulate in September,reaching the peak value in January, and accounting for 50±25% of the total area of Tianshan Mountain.Snow area began to melt in March,and reached the lowest value in August,and only accounting for 3.5±2% of the total area of Tianshan Mountains; Most of the area in the Tianshan mountains snow beginning 300 days later,the end of the snow time between 40 to 120 days,the area with high altitude, snow appeared earlier; Unstable snow areas that average number of snow cover days less than 60 days are mainly distributed in the edge of the Tianshan southern and north,accounted for 44.57% of the total area of Tianshan mountain.The average number of snow cover days between 40 to 120 days areas accounted for 44.57% of the total area of Tianshan mountain,mainly distributed in the Middle Tianshan Mountains and the northern slope of the Tianshan Mountains. The average number of snow cover days more than 300 days as the permanent snow area, mainly in the area above 3800 of the Tianshan mountains area,accounting for 2.03% of the area of the Tianshan mountains.