Work

Assessment of runoff generation capacity and total runoff contribution for different landscapes in alpine and permafrost watershed

Year: 2024

Type: article

Abstract: Alpine vegetation, cold deserts, and glacial landscapes have a significant impact on runoff generation and convergence in cold and alpine regions. The existing mountain permafrost makes these impacts more complex. To clearly understand the special regulation of alpine landscapes on runoff, the optimal variable infiltration capacity (VIC) model was applied to simulate and assess the spatiotemporal characteristics of the runoff generation capacity and contribution of different landscapes in a typical alpine permafrost watershed: The upper reaches of the Shule River (USR) basin. Glaciers, alpine meadows, cold deserts, and barren landscape zones are the four major runoff generation regions, generating approximately 95% of the USR runoff. The runoff depth in each landscape zone was calculated to express its “runoff generation capacity,” with an order of: glacier > cold desert > barren > alpine grassland > alpine meadow > shrub > swamp meadow. The alpine regions above 4000 m in altitude are the main runoff generation region, and “runoff generation capacity” gradually decreases from high altitudes to low altitudes in the alpine basin. Because of seasonal differences in rainfall distribution, glacier melting, and permafrost thawing-freezing, the dominant landscape types contributing to runoff varied monthly. Permafrost degradation makes summer runoff generated in vegetation landscape zones decrease. For example, the alpine meadow and swamp meadow landscape zones in the USR basin showed a decreasing rate of over 25% during June–August. These findings enhance our understanding of the mechanisms of runoff generation and convergence in the cold and alpine watersheds of the Northern Hemisphere.

Source: CATENA

DOI: 10.1016/j.catena.2024.108643