摘要
引入变动积雪覆盖高程(FSCE)描述积雪/裸地下垫面分界线在多年平均意义下的年内变化特征,通过参数无雪期中期Tm和无雪期持续时间ΔT对其进行量化,建立了藏东拉萨河流域、尼洋河流域和昌都地区的FSCE回归模型.统计分析表明,在25km×25km雪产品栅格分辨率下,研究区域内近80%的面积上,积雪的时空分布可以通过FSCE刻画:1)无雪期中期Tm的多年平均值为一年的7月31日,与地理地形因素相关性较弱;2)无雪期持续时间ΔT的多年平均值约为5个月(151d),与栅格平均高程显著负相关;3)一年的4月下旬积雪开始消融、6月下旬至9月中旬为无雪期,11月中旬至次年3月为积雪覆盖期.将来更高空间分辨率的雪产品数据,将有助于揭示小尺度上的FSCE精细特征.
Fluctuating snow-covered elevation（FSCE） was conceptualized and proposed to characterize within-year variation of the border between snow-covered area and snow-free area in mountainous regions.Two parameters,namely median of the snow-free period（Tm） and duration of snow-free period（DT）,were defined to quantify FSCE.A regression model of FSCE was developed for the Lhasa River basin,Niyang River basin and Changdu Prefecture in Eastern Tibet.Statistical analyses of the snow-products data with a spatial resolution of 25 km×25 km show that： 1） Tm correlates insignificantly with geographical and topographic factors,having the yearly mean value of July 31;2） DT correlates significantly with the average elevation of the snow-products cell,having the yearly mean value of nearly five months（i.e.,151 days）;3） in the region snow melting begins in last April and snow cover begins in mid November;from last June to mid September there is a snow-free period and from December to March in the next year there is a snow-cover period.In addition,snow-products with higher spatial resolution will be helpful to characterize FSCE in smaller spatial scales.
出处
《冰川冻土》
CSCD
北大核心
2011年第2期246-253,共8页
Journal of Glaciology and Geocryology
基金
科技部"十一五"科技支撑计划项目(2007BAC06B06)资助
关键词
变动积雪覆盖高程(FSCE)
藏东
无雪期中期
无雪期持续时间
回归
fluctuating snow-covered elevation
eastern Tibet
median of the snow-free period
duration of snow-free period
regression
