Global flood hazard maps can be used in the assessment of flood risk in anumber of different applications, including (re)insurance and large scaleflood preparedness. Such global hazard maps can be generated using largescale physically based models of rainfall-runoff and river routing, when usedin conjunction with a number of post-processing methods. In this study, theEuropean Centre for Medium Range Weather Forecasts (ECMWF) land surface modelis coupled to ERA-Interim reanalysis meteorological forcing data, andresultant runoff is passed to a river routing algorithm which simulatesfloodplains and flood flow across the global land area. The global hazard mapis based on a 30 yr (1979–2010) simulation period. A Gumbel distribution isfitted 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 ofhigher resolution and estimate flooded fractional area for the individual 25× 25 km cells. Several global and regional maps of flood returnperiods ranging from 2 to 500 yr are presented. The results comparereasonably to a benchmark data set of global flood hazard. The developedmethodology can be applied to other datasets on a global or regional scale.
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