Mass balance reconstruction of a reference glacier in central Asia during 2000–2023: Integrating simulation and in-situ measurements

The scarcity of observational data on the mass balance of glaciershas hindered an accurate understanding of how glaciers respond to climate. The Muz Taw Glacier, the only glacier in the Sawir Mountains that is subject to long-term monitoring, serves as a reference glacier for this study. We utilized the COSIPY model and integrated both in-situ and geodetic data on glacier mass balance to reconstruct the mass balance of Muz Taw Glacier from 2000 to 2023. Over the past 24 years, the cumulative mass balance was found to be −18.5550 m w.e., with an average annual mass balance of −0.7731 m w.e. Changes in mass balance can be categorized into two distinct phases: remarkable mass loss from 2000 to 2008, exhibiting an average annual value of −0.7973 m w.e.; followed by another comparable period from 2009 to 2017 with an average annual value of −0.8045 m w.e. A notable deceleration in mass loss occurred between 2018 and 2023, during which the average annual loss decreased to −0.6896 m w.e. Throughout 2000‒2023, Muz Taw Glacier experienced persistent mass loss influenced by multiple factors as revealed through energy budget analysis: net radiation accounted for 63%, sensible heat flux contributed 18%, latent heat flux played a minor negative role −13%, ground heat flux represented −5%, while precipitation heat flux had a negligible contribution (1%). The uncertainty analysis indicates that our reconstructed sequence of mass balance is reliable. Furthermore, climate response analysis suggests that summer temperature emerges as the predominant factor governing changes in glacial dynamics. When compared with other monitored glaciers located within adjacent westerly-dominated regions, it appears that the mass loss rate of Muz Taw Glacier has been slowing down since 2018. This study investigates the interaction between glacier and climate using a full−component glacier energy−mass balance model. It helps understand the ablation processes and mechanisms of glaciers in Central Asia and provide a basis for predicting glacier water resources.