基于MODIS的长江源区雪冰遥感监测及其变化规律分析

利用2005—2014年的MODIS积雪产品,提取长江源区积雪覆盖率,结合同期相关气象站点的逐月平均气温数据和逐月月降水量以及直门达水文站的径流数据,通过相关分析的方法,对长江源区冰雪覆盖变化规律及其变化原因进行了探讨。结果表明:2005—2014年间,长江源区冰雪覆盖率总体呈小幅度的减少趋势;每年的10月份和11月份长江源区冰雪覆盖面积达到最大值,7月份和8月份达到最小值。另外,2005—2014年的4月份,曲麻莱月均气温和月均降水量对长江源区月均冰雪覆盖度的影响为:气温呈低度负相关,降水呈高度正相关;曲麻莱月均气温和月均降水量对直门达月均径流的影响为:气温呈中度正相关,降水呈低度正相关。研究结果可为长江源区水资源管理与生态环境保护提供支撑。

Remotely-sensed Monitoring of Snow-ice in the Source Region ofChangjiang River Based on MODIS and Analysis of Its Change Rule

The ratio of snow-ice coverage in the source region of Changjiang River was extracted by using MODIS snow product.On this basis,the change rule and causes of snow-ice coverage in the source region of Changjiang River were investigated by means of correlation analysis based on monthly average temperature and monthly precipitation series data of relevant meteorological stations in the same period as well as runoff flow data of Zhimenda hydrological station.Results showed that the coverage ratios of snow-ice in the source region of Changjiang River presented a trend of slight decrease overall.The area of snow-ice coverage in the source region of Changjiang River always reached its maximum value in every October and November, and always reached its minimum value in every July and August.In addition, in April of 2005-2014, the monthly average coverage ratio of snow-ice in the source region of Changjiang River was slightly negatively related to monthly temperature of Qumalai station and highly positively related to monthly precipitation of Qumalai station;monthly runoff flow of Zhimenda had moderately positive correlation with monthly temperature of Qumalai station and low positive correlation with monthly precipitation of Qumalai station.The results can provide support for water resources management and ecological environment protection in the source region of Changjiang River.