Ocean Science www.ocean-sci.net 1812-0784 1812-0792 5 3 2009 10.5194/os-5-369-2009 http://www.ocean-sci.net/5/369/2009/ http://www.ocean-sci.net/5/369/2009/os-5-369-2009.html http://www.ocean-sci.net/5/369/2009/os-5-369-2009.pdf 369 378 2009-09-18 An ensemble study of extreme storm surge related water levels in the North Sea in a changing climate A. Sterl sterl@knmi.nl H. van den Brink H. de Vries R. Haarsma E. van Meijgaard Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, 3730 AE De Bilt, The Netherlands The height of storm surges is extremely important for a low-lying country like The Netherlands. By law, part of the coastal defence system has to withstand a water level that on average occurs only once every 10 000 years. The question then arises whether and how climate change affects the heights of extreme storm surges. Published research points to only small changes. However, due to the limited amount of data available results are usually limited to relatively frequent extremes like the annual 99%-ile. We here report on results from a 17-member ensemble of North Sea water levels spaning the period 1950–2100. It was created by forcing a surge model of the North Sea with meteorological output from a state-of-the-art global climate model which has been driven by greenhouse gas emissions following the SRES A1b scenario. The large ensemble size enables us to calculate 10 000 year return water levels with a low statistical uncertainty. In the one model used in this study, we find no statistically significant change in the 10 000 year return values of surge heights along the Dutch during the 21st century. Also a higher sea level resulting from global warming does not impact the height of the storm surges. As a side effect of our simulations we also obtain results on the interplay between surge and tide. Alexandersson, H., Schmith, T., Iden, K., and Tuomenvirta, H.: Long-term variations of the storm climate over NW Europe, Global Atmos. Oc. System, 6, 97–120, 1998. Alexandersson, H., Tuomenvirta, H., Schmidth, T., and Iden, K.: Trends of storms in NW Europe derived from an updated pressure data set, Climate Res., 14, 71–73, 2000. Bärring, L. and von Storch, H.: Scandinavian storminess since about 1800, Geophys. Res. Lett., 31, L20202, doi:10.1029/2004GL020441, 2004. Bunde, A., Eichner, J. F., Havlin, S., and Kantelhardt, J. W.: Return intervals of rare events in records with long term persistence, Physica A, 342, 308–314, 2004. Charnock, H.: Wind stress on a water surface, Q. J. Roy. Meteorol. Soc., 81, 639–640, 1955. Coles, S.: An Introduction to Statistical Modeling of Extreme Values, Springer-Verlag, Berlin, London, Heidelberg, 208~pp., 2001. Debernard, J. B. and Røed, L. P.: Future wind, wave and storm surge climate in the Northern Seas: a revisit, Tellus, 60A, 472–438, doi:10.1111/j/1600-0870.2008.00312.x, 2008. Deltacommissie: Rapport Deltacommissie, 's-Gravenhage; Staatsdrukkerij- en Uitgeverijbedrijf, 6 Delen, 1960-61. Deel I: Eindverslag en interimadviezen. Deel II-IV: Beschouwingen over stormvloeden en getijbeweging. Deel V: Onderzoekingen betreffende de opzet van het Deltaplan en de gevolgen van de werken. Deel VI: Onderzoekingen van belang voor het ontwerpen van dijken en dammen; sociaal-economische aspecten van het Deltaplan. Dutch only, 1960/61. Gerritsen, H., de Vries, H. and Philippart, M.: The Dutch Continental Shelf Model, in: Quantitative Skill Assessment for Coastal Ocean Models, edited by: Lynch, D. and Davies, A., Coastal and Estuarine Studies, 47, AGU, 1995. Horsburgh, K. J., and Wilson, C.: Tide-surge interaction and its role in the distribution of surge residuals in the North Sea, J. Geophys. Res., 112, C08003, doi:10.1029/2006JC004033, 2007. IPCC: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, UK, and New York, NY, 2007. Jungclaus, J. H., Keenlyside, N., Botzet, M., Haak, H., Luo, J. J., Latif, M., Marotzke, J., Mikolajewicz, U., and Roeckner, E.: Ocean Circulation and Tropical Variability in the Coupled Model ECHAM5/MPI-OM, J. Climate, 19, 3952–3972, 2006. Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deaven, D., Gandin, L., Iredell, M., Saha, S., White, G., Woollen, J., Zhu, Y., Chelliah, M., Ebisuzaki, W., Higgins, W., Janowiak, J., Mo, K. C., Ropelewski, C., Wang, J., Leetmaa, A., Reynolds, R., Jenne, R., and Joseph, D.: The NCEP/NCAR reanalysis project, B. Am. Meteorol. Soc., 77, 437–471, 1996. KNMI: KNMI Climate Change Scenarios 2006 for The Netherlands, KNMI Scientific report WR 2006-01. Available from KNMI, P.O. Box 201, 3730 AE De Bilt, The Netherlands, 2006. Lowe, J. A., Gregory, J. M., and Flather, R. A.: Changes in the occurrence of storm surges around the United Kingdom under a future climate scenario using a dynamic storm surge model driven by the Hadley Centre climate models, Clim. Dynam., 18, 179–188, 2001. Lowe, J. A. and Gregory, J. M.: The effects of climate change on storm surges around the Unitied Kingdom, Philos. T. Roy. Soc., A363, 1313–1328, doi: 10.1098/rsta.2005.1570, 2008. Meehl, G. A., Covey, C., Delworth, T., Latif, M., McAvaney, B., Mitchell, J. F. B., Stouffer, R. J., and Taylor, K. E.: The WCRP CMIP3 multi-model dataset: A new era in climate change research, B. Am. Meteorol. Soc., 88, 1383–1394, 2007. Nakicenovic, N. and Swart, R. (Eds.): Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK, 599~pp., online available at: http://www.grida.no/climate/ipcc/emission/index.htm, 2000. Räisänen, J., Hansson, U., Ullerstig, A., Döscher, R., Graham, L., Jones, C., Meier, H., Samuelsson, P., and Willén, U.: GCM driven simulations of recent and future climate with the Rossby Centre coupled atmosphere-Baltic Sea regional climate model RCAO, SMHI, Norrköping, Rossby Centre, 61~pp., 2003. Sterl, A., Severijns, C., Dijkstra, H., Hazeleger, W., van Oldenborgh, G. J., van den Broeke, M., Burgers, G., van den Hurk, B., van Leeuwen, P. J., and van Velthoven, P.: When can we expect extremely high surface temperatures?, Geophys. Res. Lett., 35, L14703, doi:10.1029/2008GL034071, 2008. Uppala, S. M., Kållberg, P. W., Simmons, A. J., Andrae, U., V. da Costa Bechtold, Fiorino, M., Gibson, J. K., Haseler, J., Hernandez, A., Kelly, G. A., Li, X., Onogi, K., Saarinen, S., Sokka, N., Allan, R. P., Andersson, E., Arpe, K., Balmaseda, M. A., Beljaars, A. C. M., van de Berg, L., Bidlot, J., Bormann, N., Caires, S., Chevallier, F., Dethof, A., Dragosavac, M., Fisher, M., Fuentes, M., Hagemann, S., Hólm, E., Hoskins, B. J., Isaksen, L., Janssen, P. A. E. M., Jenne, R., McNally, A. P., Mahfouf, J.-F., Morcrette, J.-J., Rayner, N. A., Saunders, R. W., Simon, P., Sterl, A., Trenberth, K. E., Untch, A., Vasiljevic, D., Viterbo, P., and Woollen, J.: The ERA-40 re-analysis, Q. J. Roy. Meteorol. Soc., 131, 2961–3012, 2005. Van den Brink, H. W., Können, G. P., and Opsteegh, J. D.: The reliability of extreme surge levels, estimated from observational records of order hundred years, J. Coast. Res., 19, 376–388, 2003. Van Den Brink, H. W., Können, G. P., Opsteegh, J. D., van Oldenborgh, G. J., and Burgers, G.: Improving 10$^4$-year surge level estimates using data of the ECMWF seasonal prediction system, Geophys. Res. Lett., 31, L17210, doi:10.1029/2004GL020610, 2004. Van den Brink, H. W. and Können, G. P.: The statistical distribution of meteorological outliers, Geophys. Res. Lett., 35, L2370, doi:10.1029/2008GL035967, 2008. Van Meijgaard, E., van Ulft, L. H., van de Berg, W. J., Bosveld, F. C., van den Hurk, B. J. J. M., Lenderink, G., and Siebesma, A. P.: The KNMI regional atmospheric climate model RACMO, version 2.1, KNMI Technical Report TR-302, available from KNMI, P.O Box 201, NL-3730 AE De Bilt, The Netherlands, 43~pp., 2008. Van Ulden, A.P., and Van Oldenborgh, G.J.: Large-scale atmospheric circulation biases and changes in global climate model simulations and their importance for climate change in Central Europe, Atmos. Chem. Pys. 6, 863–881, Sref-ID: 1680-7324/acp/2006-6-863, 2006. The WASA-Group: Changing waves and storms in the Northeast Atlantic?, B. Am. Meteorol. Soc., 79, 741–760, 1998. Woth, K.: North Sea storm surge statistics based on projections in a warmer climate: How important are driving GCM and the chosen emission scenario?, Geophys. Res. Lett., 32, L22708, doi:10.1029/2005GL023762, 2005. Woth, K., Weisse, R., and von Storch, H.: Climate change and North Sea storm surge extremes: an ensemble study of storm surge extremes expected in a changed climate projected by four different regional climate models, Ocean Dynam., 56, 3–15, doi:10.1007/s10236-005-0024-3, 2006.