Spatial and temporal patterns of large-scale droughts in Europe: Model dispersion and performance

This study explores the performance of a suite of off-line, global (hydrological and land surface) models in mapping spatial and temporal patterns of large-scale hydrological droughts in Europe from simulated runoff in the period 1963-2000. Consistent model behavior was found for annual variability in mean drought area, whereas high model dispersion was revealed in the weekly evolution of contiguous area in drought and its annual maximum. Comparison with nearly three hundred catchment-scale streamflow observations showed an overall tendency to overestimate the number of drought events and hence underestimate drought duration, whereas persistence in drought-affected area (weekly mean) was underestimated, noticeable for one group of models. The high model dispersion in temporal and spatial persistence of drought identified implies that care should be taken when analyzing drought characteristics from only one or a limited number of models unless validated specifically for hydrological drought. Key Points Models are able to reproduce the ranking of the most extreme droughts in Europe Model dispersion is high in simulating temporal and spatial drought persistence Model validation reveals a tendency to overestimate the number of drought events