High-resolution glacier mapping reveals inventory biases and terrain controls on debris-covered glaciers in the Karakoram

Abstract. Accurate glacier inventories are fundamental for quantifying glacier change, estimating ice volume and assessing meltwater resources. However, medium-resolution inventories often fail to resolve critical glacier characteristics in topographically complex and debris-rich mountain environments. Here, we present the 2 m Karakoram Glacier Inventory (2mKGI), developed from high-resolution ZY-3 optical imagery, a co-registered ZY-3 digital elevation model (DEM) and auxiliary optical datasets through an integrated deep-learning and manual-refinement framework. The inventory identifies ~13,900 glaciers covering 21,261.8 ± 278 km², including 2,239.9 ± 82.8 km² of supraglacial debris, with an overall mapping uncertainty of ±4.7 %. Comparison with existing inventories reveals that previous medium-resolution products commonly underestimate glacier numbers while simultaneously overgeneralizing debris-covered glacier margins. These biases substantially influence glacier-count statistics, estimates of debris-covered area, and the interpretations of glacier-change signals. The newly identified glaciers are mostly <0.1 km². Despite their limited area, their thin ice and shorter response times may make them particularly sensitive to warming. Topographic analysis further demonstrates that supraglacial debris is preferentially distributed across low-elevation and low-slope glacier tongues, highlighting the strong controls of valley geometry, ice transport processes, and ablation-zone morphology on debris persistence. The 4 m ZY-3 DEM highlights that high-resolution topographic information improves the delineation of glacier-units, accumulation–ablation zone structure and debris-covered tongues by preserving steep headwalls, slope discontinuities, tributary junctions, local relief and low-gradient terrain. The 2mKGI will provide a high-resolution geometric and topographic benchmark for glacier-change assessment, ice-thickness inversion, glacier-evolution modelling and next-generation automated glacier mapping in the Karakoram.