Evaluation of drought propagation in an ensemble mean of large-scale hydrological models

• DOI: 10.5194/hess-16-4057-2012
• Publication Date: 2012-11-06T10:32:56Z
• Authors: A. F. Van Loon; M. H. J. Van Huij...; H. A. J. Van Lanen
• Keywords: Water cycle; Hydrological modelling; Snowmelt

Abstract. Hydrological drought is increasingly studied using large-scale models. It is, however, not sure whether models reproduce the development of hydrological correctly. The pressing question how well do simulate propagation from meteorological to drought? To answer this question, we evaluated simulation in an ensemble mean ten models, both land-surface and global that participated model intercomparison project WATCH (WaterMIP). For a selection case study areas, characteristics (number droughts, duration, severity), features (pooling, attenuation, lag, lengthening), typology (classical rainfall deficit drought, rain-to-snow-season wet-to-dry-season cold snow season warm composite drought). Drought simulated by clearly reflected propagation; i.e. events became fewer longer when moving through cycle. However, more differentiation was expected between fast slowly responding systems, with systems having droughts runoff than systems. This found were poorly reproduced because reacted immediately precipitation, all areas. reaction even climates winter semi-arid summer, also greatly influenced as identified In general, had correct representation types, but percentages occurrence some important mismatches, e.g. overestimation classical underestimation snow-related droughts. Furthermore, almost no for while many multi-year these We conclude most processes are reasonably contrasting catchments Europe. Challenges, remain large storage aquifers or lakes. leads high uncertainty at scales. Improvement should focus on better development, such evapotranspiration, accumulation melt, especially storage. Besides explicit inclusion parametrisation requires attention, example global-scale dataset aquifer characteristics, improved datasets other land (e.g. soils, cover), calibration/evaluation against observations snow, groundwater).