Glacier changes in the Sanjiangyuan Nature Reserve of China during 2000–2018

The glaciers in the Sanjiangyuan Nature Reserve of China (SNRC) are a significant water resource for the Yangtze, Yellow, and Mekong rivers. Based on Landsat Thematic Mapper (TM)/Operational Land Imager (OLI) images acquired in 2000, 2010, and 2018, the outlines of glaciers in the SNRC were obtained by combining band ratio method with manual interpretation. There were 1714 glaciers in the SNRC in 2018, with an area of 2331.15±54.84 km2, an ice volume of 188.90±6.41 km3, and an average length of 1475.4±15 m. During 2000–2018, the corresponding values of glaciers decreased by 69, 271.95±132.06 km2, 18.59±8.83 km3, and 84.75±34 m, respectively. Glaciers in the Yangtze River source area witnessed the largest area loss (−154.45 km2), whereas glaciers in the Mekong River source area experienced the fastest area loss (−2.02%·a−1) and the maximum reduction of the average length (−125.82 m). Overall, the retreat of glaciers in the SNRC exhibited an accelerating trend. Especially, the loss rate of glacier area in the Yellow River source area in 2010–2018 was more than twice that in 2000–2010. The glacier change is primarily attributed to the significant rise in temperature during the ablation period. Some other factors including the size, orientation and terminus elevation of glaciers also contributed to the heterogeneity of glacier change.