Simulating Future Runoff in a Complex Terrain Alpine Catchment with EURO-CORDEX Data

• DOI: 10.1175/jhm-d-18-0214.1
• Publication Date: 2019-07-17T17:41:05Z
• Authors: Gerhard Smiatek; Harald Kunstmann
• Keywords: Hydrometeorology; Forcing (mathematics); Snowmelt

Abstract With large elevation gradients and high hydrometeorological variability, Alpine catchments pose special challenges to hydrological climate change impact assessment. Data from seven regional models run within the Coordinated Regional Climate Downscaling Experiments (CORDEX), each driven with a different boundary forcing, are used exemplarily evaluate reproduction of observed flow duration curves access future discharge Ammer River located in southern Germany applying simulation model called Water Flow Balance Simulation Model (WaSiM). The results show that WaSiM reasonably reproduces runoff for entire catchment when precipitation. When applied CORDEX evaluation data (1989–2008) forced by ERA-Interim, simulations underestimate extreme reproduce percentile values errors range −37% 55% an ensemble mean around 15%. Runs historical 1975–2005 reveal larger errors, up 120%, 50% overestimation. Also, spread between simulations, primarily resulting deficiencies precipitation data. Results indicate changes 2071–2100 99.5th value 9% compared 1975–2005. An increase flows is also supported return periods obtained sample highest over 50 years, which reveals 2051–2100 lower 1956–2005. Obtained associated substantial uncertainties leading conclusion at 0.11° resolution likely inadequate driving hydrologic analyses mesoscale require standard fidelity performance.