| 29 Jan 2026
High-resolution monthly glacier surface velocity mapping in the Kangri Karpo region (2015–2024) using multi-source remote sensing data fusion
Abstract. To improve the accuracy and timeliness of glacier surface-velocity retrieval in complex mountain terrain, we develop a high-resolution fusion method combining Landsat, Sentinel-1/2, and UAV (Unmanned Aerial Vehicle) data, and produce monthly velocity products for the Kangri Karpo region for 2015–2024. Compared with existing large-area public datasets, the products offer markedly higher spatial resolution and better detection of small mountain glaciers; relative to single-sensor inputs prior to fusion, the valid-pixel ratio increases by ~50 %, the average number of valid months per pixel over the decade rises by ~50, and spatial smoothness improves—demonstrating the method’s suitability for rugged terrain. Spatially, velocities follow the canonical “fast center, slow margins” pattern, with multi-year maxima >700 m·yr⁻¹ and values in lower reaches and most tributaries generally <100 m·yr⁻¹. Attribute analysis indicates significant correlations between velocity and area, slope, and aspect: larger glaciers flow faster overall; within individual glaciers, velocity responds more strongly to slope; after controlling for area and slope, south-facing glaciers are slightly faster. Temporally, the intra-annual series shows clear seasonality, with peaks at the beginning and end of the melt season and sustained high speeds throughout. At the interannual scale, most pixelwise decadal trends lie within −0.1 to +0.1 m·d⁻¹·dec⁻¹ (overall subdued change), and the median trend is slightly positive, indicating weak regional acceleration; ~38.3 % of glaciers accelerate significantly, 25.5 % decelerate significantly, and 36.2 % show no significant trend (p ≥ 0.05). By aspect, significant acceleration is concentrated on south- and west-facing glaciers, whereas significant deceleration occurs mainly on east- and north-facing glaciers. Month-resolved trends indicate acceleration primarily in April–May (~0.15–0.20 m·d⁻¹·dec⁻¹), likely linked to enhanced meltwater input from an advanced melt season, and deceleration concentrated in July–August (≤ −0.15 m·d⁻¹·dec⁻¹), plausibly associated with intensified mass deficit.
Competing interests: At least one of the (co-)authors is a member of the editorial board of The Cryosphere.
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