Modelling the energy and mass balance of the Ányêmaqên Mountain glaciers in the source region of the Yellow River on the Tibetan Plateau

Under the context of global warming, the mechanism of glacier shrinkage has become a central focus in cryospheric research. The Ányêmaqên Mountain is the most densely distributed glacier area in the source region of the Yellow River on the Tibetan Plateau, and it is highly sensitive to climate change. This study utilized the distributed Coupled Snowpack and Ice Energy and Mass Balance Model (COSIMA), integrating High Asia Refinement Analysis (HAR) data and meteorological station observations, to simulate spatiotemporal patterns of energy and mass balance for Ányêmaqên Mountain glaciers. The results demonstrated an annual glacier mass balance of -0.50 m w.e. from 1 January 2021 to 31 December 2023, with substantial mass loss (peaking at -5.4 m w.e.) observed in zones below 5300 m a.s.l., notably the Halong, Weigeledangxiong, and Yehelong glaciers. The main energy sources for glacier melt were net shortwave radiation (79.38%), sensible heat flux (12.31%) and ground heat flux (8.30%). The main expenditure items of energy included net longwave radiation (67.05%), available heat for melt (14.97%) and latent heat flux (17.98%). Solid precipitation accounted for 95% of the accumulation of glacier mass balance, and melt-water refreezing accounted for 5.0%. Sensitivity experiments revealed that rising air temperatures and declining precipitation were the principal drivers of mass loss, with a 1 K temperature increase requiring a 20% annual precipitation increase to offset equivalent mass loss. The mass loss of glaciers was mainly caused by superimposed ice surface ablation and subsurface ablation. This study is an important reference for a deeper understanding of the glacier’s response to climate change in the source region of Yellow River.