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

Abstract

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.

Multiscale evaluation of the Standardized Precipitation Index as a groundwater drought indicator

“…We note that the approach chosen here is consistent with that commonly used in previous groundwater studies (e.g., Bloomfield and Marchant, 2013;Li and Rodell, 2015). On the other hand, the grid-scale analysis was carried out using the monthly estimates of drought indices gridded at a 0.5 • spatial resolution -the scale that is commonly used in regional-and global-scale drought studies (e.g., Sheffield et al, 2004;Andreadis et al, 2005;Gudmundsson et al, 2012;Seneviratne et al, 2012;Van Loon et al, 2012;Tallaksen and Stahl, 2014;Wanders et al, 2015). The gridded fields of drought indices were estimated using a procedure similar to the ones employed in creating multi-model drought indices (see, e.g., Mo and Lettenmaier, 2013;Nijssen et al, 2014).…”

“…An extensive multi-model study (Prudhomme et al, 2014), for example, projected increases in hydrological drought severity in many areas around the world. This approach also has limitations in its application to local-to regional-scale hydrological drought monitoring because of scale mismatches and some issues in the correct representation of storage in models (Gudmundsson et al, 2012;Van Loon et al, 2012;Tallaksen and Stahl, 2014). The importance of spatial variation in groundwater drought conditions resulting from complexity in subsurface conditions is increasingly recognized (Peters et al, 2006;Bloomfield and Marchant, 2013;Stoelzle et al, 2014).…”

Towards observation-based gridded runoff estimates for Europe

“…While the monthly resolution may limit its ability to capture flash floods, it is still suitable for observing slowly evolving phenomena that are relevant for water resources management such as droughts. In Europe, 1976 is documented as a year with one of the most severe droughts of the twentieth century (Zaidman et al, 2002;Briffa et al, 2009;Tallaksen and Stahl, 2014). The severity of this drought is illustrated in Fig.…”

Spatiotemporal dynamics of global drought

“…However, the regional scale of these studies still bounds the frame of analysis and prevents a thorough comparison of the spatio-temporal characteristics of drought across the globe. Furthermore, previous studies have been limited to simple assessments of the time series of drought area and intensity [Vicente-Serrano, 2006;Vidal et al, 2010;Gocic et al, 2014;Wang et al, 2015], report aggregate regional drought statistics that do not provide insight into the behavior of individual events [Tallaksen and Stahl, 2014;Ge et al, 2016].…”