Abstract: 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.

Key words: the source region of Changjiang River, MODIS snow product, area of snow-ice coverage, air temperature, precipitation, runoff