Print Email Facebook Twitter Improving sea-level projections on the Northwestern European shelf using dynamical downscaling Title Improving sea-level projections on the Northwestern European shelf using dynamical downscaling Author Hermans, T.H.J. (TU Delft Physical and Space Geodesy; Universiteit Utrecht) Tinker, Jonathan (Met Office) Palmer, Matthew D. (Met Office) Katsman, C.A. (TU Delft Environmental Fluid Mechanics) Vermeersen, L.L.A. (TU Delft Physical and Space Geodesy; TU Delft Astrodynamics & Space Missions; Universiteit Utrecht) Slangen, Aimée B.A. (Universiteit Utrecht) Date 2020 Abstract Changes in ocean properties and circulation lead to a spatially non-uniform pattern of ocean dynamic sea-level change (DSLC). The projections of ocean dynamic sea level presented in the IPCC AR5 were constructed with global climate models (GCMs) from the Coupled Model Intercomparison Project 5 (CMIP5). Since CMIP5 GCMs have a relatively coarse resolution and exclude tides and surges it is unclear whether they are suitable for providing DSLC projections in shallow coastal regions such as the Northwestern European Shelf (NWES). One approach to addressing these shortcomings is dynamical downscaling – i.e. using a high-resolution regional model forced with output from GCMs. Here we use the regional shelf seas model AMM7 to show that, depending on the driving CMIP5 GCM, dynamical downscaling can have a large impact on DSLC simulations in the NWES region. For a business-as-usual greenhouse gas concentration scenario, we find that downscaled simulations of twenty-first century DSLC can be up to 15.5 cm smaller than DSLC in the GCM simulations along the North Sea coastline owing to unresolved processes in the GCM. Furthermore, dynamical downscaling affects the simulated time of emergence of sea-level change (SLC) above sea-level variability, and can result in differences in the projected change of the amplitude of the seasonal cycle of sea level of over 0.3 mm/yr. We find that the difference between GCM and downscaled results is of similar magnitude to the uncertainty of CMIP5 ensembles used for previous DSLC projections. Our results support a role for dynamical downscaling in future regional sea-level projections to aid coastal decision makers. Subject Dynamical downscalingGlobal climate modelsNorthwestern European shelfRegional sea levelSea-level projectionsSea-level variability To reference this document use: http://resolver.tudelft.nl/uuid:37471904-2efa-4ab0-9e94-e60e6dc07e01 DOI https://doi.org/10.1007/s00382-019-05104-5 ISSN 0930-7575 Source Climate Dynamics: observational, theoretical and computational research on the climate system, 54 (3-4), 1987-2011 Part of collection Institutional Repository Document type journal article Rights © 2020 T.H.J. Hermans, Jonathan Tinker, Matthew D. Palmer, C.A. Katsman, L.L.A. Vermeersen, Aimée B.A. Slangen Files PDF Hermans2020_Article_Impro ... tionsO.pdf 8.86 MB Close viewer /islandora/object/uuid:37471904-2efa-4ab0-9e94-e60e6dc07e01/datastream/OBJ/view