西藏东部山区积雪高程的年内变化特征及其量化
Characterization and Quantification of Within-year Variation of Snow-Cover Elevation in Mountainous Regions, Eastern Tibet
高洁 1傅旭东 1巩同梁 2王光谦 1王远见 1王皓1
作者信息
- 1. 清华大学水沙科学与水利水电工程国家重点实验室,北京,100084
- 2. 清华大学水沙科学与水利水电工程国家重点实验室,北京,100084;西藏自治区水利厅,西藏,拉萨,850000
- 折叠
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△T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25 km×25 km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△T的多年平均值约为5个月(151 d),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.
Abstract
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 snowfree 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 snowfree 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.
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Key words
fluctuating snow-covered elevation/eastern Tibet/median of the snow-free period, duration of snow-free period/regression引用本文复制引用
基金项目
科技部"十一五"科技支撑计划项目(2007BAC06B06)
中国西部环境与生态科学数据中心项目(90502010)
中国西部地区陆面数据同化系统研究(90202014)
出版年
2011
NETL
NSTL
维普
万方数据