Articles | Volume 16, issue 11
Hydrol. Earth Syst. Sci., 16, 4143–4156, 2012
https://doi.org/10.5194/hess-16-4143-2012
Hydrol. Earth Syst. Sci., 16, 4143–4156, 2012
https://doi.org/10.5194/hess-16-4143-2012

Research article 09 Nov 2012

Research article | 09 Nov 2012

Deriving global flood hazard maps of fluvial floods through a physical model cascade

F. Pappenberger1,2, E. Dutra1, F. Wetterhall1, and H. L. Cloke1,3 F. Pappenberger et al.
  • 1European Centre for Medium Range Weather Forecasts, Reading, UK
  • 2College of Hydrology and Water Resources, Hohai University, Nanjing, China
  • 3Department of Geography and Environmental Science and Department of Meteorology, University of Reading, Reading, UK

Abstract. Global flood hazard maps can be used in the assessment of flood risk in a number of different applications, including (re)insurance and large scale flood preparedness. Such global hazard maps can be generated using large scale physically based models of rainfall-runoff and river routing, when used in conjunction with a number of post-processing methods. In this study, the European Centre for Medium Range Weather Forecasts (ECMWF) land surface model is coupled to ERA-Interim reanalysis meteorological forcing data, and resultant runoff is passed to a river routing algorithm which simulates floodplains and flood flow across the global land area. The global hazard map is based on a 30 yr (1979–2010) simulation period. A Gumbel distribution is fitted to the annual maxima flows to derive a number of flood return periods. The return periods are calculated initially for a 25 × 25 km grid, which is then reprojected onto a 1 × 1 km grid to derive maps of higher resolution and estimate flooded fractional area for the individual 25 × 25 km cells. Several global and regional maps of flood return periods ranging from 2 to 500 yr are presented. The results compare reasonably to a benchmark data set of global flood hazard. The developed methodology can be applied to other datasets on a global or regional scale.

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