基于MODIS积雪产品的中国天山山区积雪时空分布特征研究

摘要

Daily snow cover products in clear sky of Tianshan area from 2002 to 2016 were obtained from MODIS products of daily snow (MOD10A1,MYD10A1),combining the existed cloud removal method,near day analysis method,temporal filter method and spatial filter method. Then the temporal and spatial distribution characteristics of snow cover in Tianshan Mountains were investigated. It is found that the average snow cover area in Tianshan Mountains decreased slightly in the recent 15 years and interannual fluctuation changed significantly. Snow cover area of Tianshan mountain showed clearly seasonal variations in the following sequence: winter > autumn >spring >summer. Snow area began to accumulate in September,and reached the peak value in January,accounting for 25%~75%of the total area of Tianshan Mountains. Snow area began to melt in March,and reached the lowest value in August,only accounting for 1.5%~5.5%of the total area of Tianshan Mountains;Most of the area in the Tianshan mountains snow began to appear after 300 days,the end of the snow time was between 40 to 120 days,snow appeared earlier in the high altitude area. The aeras of average number of snow cover days less than 60 days mainly distributed in the edge of the Tianshan southern and north,accounting for 44.57% of the total area. The aeras of average number of snow cover days between 60 to 300 days mainly distributed in the Middle Tianshan Mountains and the northern slope of the Tianshan Mountains,accounting for 44.57% of the total area. The aeras of average number of snow cover days more than 300 days mainly distributed in the area above sea level 3800 m of the Tianshan mountains area,accounting for 2.03%of the total area.%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,分析天山山区积雪时空分布特征.结果表明:近15 a,天山山区平均积雪覆盖面积呈略微减少趋势,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25%~75%,3月开始消融,8月达到最低值,仅占天山总面积的1.5%~5.5%.天山山区大部分区域积雪开始时间在第300 d之后,积雪结束时间在第40~150 d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 d的区域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 d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 d的积雪区主要分布在海拔3800 m以上区域,占天山面积的2.03%.