Glacier distribution and changes in Yarkant River Basin, southwestern Tarim Basin

Based on the Chinese Glacier Inventory of Xinjiang in 2020 (CGI-XJ2020), this study analyzed the spatial distribution of glaciers in the Yarkant River Basin and, together with the First Chinese Glacier Inventory (CGI-1), investigated glacier changes from 1968 to 2020. The results show that the Yarkant River is a transboundary basin containing 5,301 glaciers, with a total area of 5,836.29 km 2 and an estimated ice volume of 418.16 km 3 . The mean glacier area is 1.1 km 2 . Of these, 4,948 glaciers with a total area of 5,182.07 km 2 are located in China, including 392 debris-covered glaciers covering 206.30 km 2 . In Pakistan, 353 glaciers cover 654.22 km 2 , of which 159 are debris-covered and occupy 77.29 km 2 . The Karakoram Mountains are the principal glacierized area, accounting for 78.25% of the total glacier area, followed by the West Kunlun Mountains and the Pamirs. Most glaciers are concentrated between 5,000 and 6,000 m, accounting for 83.50% of the total area. Among the sub-basins, the Shaksgam River Basin has the largest glacier area, whereas the Tiznaf River Basin has the smallest. Comparison of the two glacier inventories using the glacier code matching method shows that, from 1968 to 2020, the mean annual retreat rate of matched glacier area in the Yarkant River Basin was 0.35%/a. Based on the initial glacier area of 6,237.51 km 2 in 1968 and this retreat rate, the total glacier area is estimated to have decreased by 1,135.23 km 2 over the study period. Overall, smaller glaciers showed higher relative retreat rates, whereas larger glaciers experienced greater absolute area loss. Among the sub-basins, the Taxkorgan River Basin (5Y656) retreated the fastest, with a total area loss rate of 27.52% and a mean annual retreat rate of 0.53%.