基于MODIS的祁连山区积雪时空变化特征

The Spatial and Temporal Variations of Snow Cover over the Qilian Mountains Based on MODIS Data

利用2000-2003年日资料经8d合成的500m分辨率MODIS卫星反演积雪资料和数字高程模型,借助于GIS空间分析技术,以积雪频率和积雪盖度为监测指标,研究分析了祁连山区整体的积雪空间分布状况及其年内变化特征,地形对积雪的分布和季节变化的影响.结果表明:祁连山区的积雪分布极不均匀,积雪主要沿山系走向成条带状分布,呈现西段多,东段次之,中部和南部少,山脊多,山谷少的特征,且海拔越高、山势越陡、阴坡积雪的范围越大、持续时间越久.累积降雪时间,就全区而言为9月至翌年5月,但不同高度、坡度和坡向带有所差别.海拔4000m以上区域存在春、秋季两个时段的积雪补给,而海拔4000m以下仅有中秋至中冬一个时段的积雪补给;坡度较平缓的区域冬季和春季为主要积雪补给期,而坡度较陡的区域则为秋季和春季;平地和南坡积雪补给主要发生在冬季和春季,而其它坡向为春季和秋季.

Based on MOD10A2 snow cover products at a spatial resolution of 500 m and 8-day interval from February 2000 to February 2003 and digital elevation model,the spatial distributions and seasonal variations of snow cover in the whole area and for different terrains over the Qilian Mountains were studied via monitoring the frequency and coverage of snow cover,supported by spatial analysis of GIS. The results show that the spatial distribution of snow cover over the Qilian Mountains is far from uniformity. Snow c...