资源环境科技发展态势分析平台

The Third Pole experiences accelerated glacier retreating particularly in the eastern Himalaya, coinciding with a decrease of monsoon-precipitation in the early 21^st century. The extent to which the vanishing abundant maritime glaciers buffer the declining precipitation-runoff remains unclear. Here, with a state-of-the-art enthalpy-based distributed cryosphere-hydrology model and first-hand hydrometeorology observations at Motuo (latest accessible Chinese county), we carefully examine the Yarlung Zangbo basin along Himalayas. We find that during 1998-2019, the rising downstream runoff (lower Nuxia; +6.40×10⁸ m³/yr) offsets the dropping upstream runoff (upper Nuxia; -6.89×10⁸ m³/yr); however, only the marginal contribution from the vanishing eastern-Himalaya and Nyainqêntanglha glaciers. During 1998-2019, dry upstream illustrates limited glacier-melt (15.7 mm/yr) with dominated snow-melt (78.8 mm/yr); while much larger at humid downstream (144.8 mm/yr for glacier-melt and 219.1 mm/yr for snow-melt). From 1981 to 2019, we observe glacier-to-snow melt transition in both up- and downstream due to glacier degradation and growing non-monsoon-season precipitation.