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Accurately quantifying runoff sources and understanding hydrological processes in glaciated mountain basins is essential for effective water resource management in the face of climate change. This study aimed to determine the contributions from various runoff sources in glaciated basins within the inner Tien-Shan mountains of Kyrgyzstan by utilizing integrated land surface, glacier energy-mass balance, and river routing models. To account for local topographic influences on solar radiation and cloud transmissivity processes, gridded meteorological forcing data were downscaled. The integrated models were then evaluated against observed discharge, glacier mass balance, and snow water equivalent, with a focus on the Kara-Batkak glacier reference site. Shortwave radiation correction was particularly important for improving the accuracy of model simulations. The results indicate that the peak glacier melt contribution occurs in July and August, with some basins reaching up to 54%. On an annual basis, the average contribution from glaciers across the basins was found to be 19%, while the ratios of snowmelt and rainfall were 58% and 23%, respectively. This study highlights the utility of integrated modelling approaches in understanding and quantifying runoff components in data-scarce high mountain regions. The incorporation of observed glacier data proved to be crucial for accurately representing hydrological processes under current climatic conditions. These findings underscore the significance of considering glacier dynamics and their influence on water resources to inform effective water management strategies in glaciated mountain basins. [ABSTRACT FROM AUTHOR]

An accurate ice thickness distribution is crucial for correct projections of the future state of an ice mass. However, measuring the ice thickness with an in-situ system is time-consuming and not scalable. Therefore, models have been developed that estimate the ice thickness without direct measurements. In this study, we reconstruct the ice thickness of the Grigoriev ice cap, Kyrgyzstan, from in-situ observations and the yield stress method. We compare the results with data from 6 global ice thickness datasets composed without the use of our local measurements. The results highlight shortcomings of these generic datasets and demonstrate the importance of local observations for accurate representations of the ice thickness. [ABSTRACT FROM AUTHOR]

High Mountain Asia (HMA) contains the largest concentration of glaciers outside the polar regions. These glaciers play an essential role in terms of water supply for the surrounding densely populated dry lowland areas. The retreat of glaciers and ice caps in this region can consequently have a major impact on societies. However, few modelling studies exist that examine in detail how individual ice bodies in the area are responding to climate change. Further, different climatic and topographic settings ensure a heterogenous impact of climate change on ice masses in the area. In this study, we focus on the western and central part of the Tien Shan Mountain range in the northwest of HMA. We use several measurements and reconstructions of the ice thickness, surface elevation, surface mass balance and ice temperature to study in detail six different ice bodies in the Kyrgyz Tien Shan: five valley glaciers and one ice cap. The selected ice masses are located in different sub-regions of the Tien Shan with different climatic settings, and they are all characterised by detailed recent glaciological measurements. A 3-dimensional higher-order thermomechanical ice-flow model is calibrated and applied to simulate the evolution of the ice masses since the Little Ice Age and to make a prognosis of the future evolution up to 2100 under different CMIP6 SSP climate scenarios. Further, projections of the total runoff of the ice masses are calculated. The results of this study reveal a strong retreat of most of the ice masses under all climate scenarios, however with important differences. These can be related to the specific climate regime of each of the ice bodies and their geometry. It is highlighted that because the main precipitation occurs in spring and early summer, the ice masses respond to climate change with an accelerating retreat. [ABSTRACT FROM AUTHOR]