天山胜利达坂地区积雪分布特征

摘要

本研究利用天山胜利达坂地区2014-2016年Landsat系列卫星的57景ETM+或OLI遥感影像,基于SNOMAP算法提取研究区积雪面积,并结合DEM数据研究了海拔高度、坡向和坡度对研究区积雪空间分布的影响.结果表明,随着海拔的增加,积雪覆盖率持续增加;阴坡积雪覆盖率约是阳坡的2～3倍.进一步的一般线性模型(GLM)分析表明:海拔、坡向和坡度均显著影响积雪的空间分布,但各地形因子的影响程度在不同季节有所差异.在冬季(12 ～2月),坡向是影响积雪覆盖率空间变异的主要地形因子,贡献了积雪覆盖率总变异的57％,约是海拔的2倍,坡度的4.5倍.对其他季节而言,海拔是主要影响因子,其次是坡向,坡度的影响最小.%An algorithm of SNOMAP was used to extract the information of snow coverage in the Shenglidaban Area,Tianshan Mountains from remote sensing images.A total of 57 Landsat images (ETM + and OLI) ranging in 2014-2016 were collected and processed for the extraction.A digital elevation model (DEM) data with a resolution of 30 m was used to obtain the topography information of the snow covered area,which was mainly expressed as index of elevation,topographic aspect and slope.It was shown that the mean annual snow coverage increased as the elevation increases,and the snow coverage on north-facing slopes was about 2 ～ 3 times more than that on south-facing slopes.An analysis based on general linear model (GLM) indicated that the spatial patterns of snow cover in this area were significantly affected by elevation,aspect and slope,and the effects of topographic factors varied greatly in different seasons.During wintertime (from Dec.to Feb.),the topographic aspect was the dominant factor affecting the distribution of snow cover,which accounted for 57％ of the overall variance in the annual snow coverage.The effect from aspect was approximately twice of elevation and four-and-a-half of slope,respectively.During the other seasons,however,elevation was the dominant affecting factor,and followed by topographic aspect and slope.