Understanding the role of rock glaciers as a water resource in the Northern Tien Shan

The cryosphere in High Mountain Asia supplies water to a quarter of a billion people; in the semi-arid Northern Tien Shan, climate change poses a serious threat to meltwater resources. Rock glaciers are prevalent across the region and represent a currently unquantified hydrological resource. This thesis advances methods for assessing ice storage within rock glaciers by investigating the relationships between surface flow and subsurface internal structure. Rock glacier surface kinematics were investigated using feature-tracking methods to detect spatial flow patterns, comparing outputs from different optical image sources. A regional velocity inventory covering 672 landforms was generated from Sentinel-2 data and high-resolution analyses conducted on 21 rock glaciers in the Ulken Almaty region. Many rock glaciers showed distinct areas of activity > 2myr⁻¹ and spatial heterogeneity in surface kinematics, reflected by bimodal distributions in velocity magnitude. Comparison with topographic parameters suggested topography does not fully explain these velocity characteristics. The subsurface structure of four landforms was investigated through Electrical Resistivity Tomography and Ground Penetrating Radar surveys. Delineation of geomorphic units identified a glacially controlled zone and a periglacial zone. The transition between these zones was characterised by a kinematic shift from incoherent to coherent flow, reflecting a subsurface transition from massive ice to composite material. A global literature synthesis examined how glacial-periglacial interactions influence rock glacier dynamics, supported by a case study from the Northern Tien Shan. In ice–debris complexes, glacial ice is often preserved under periglacial conditions, and glacier connections control material inputs to the downslope rock glacier. As a result, these rock glaciers are likely to follow a non-linear evolution trajectory under climate warming. Future research should prioritise quantifying rock glacier water volume equivalents using borehole surveys or petrophysical inversion methods, acquiring temporal velocity data to assess climate response, and critically considering the classification of landform boundaries within ice-debris complexes.