A drought climatology for Europe (original) (raw)
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Meteorology and Atmospheric Physics
One of the negative consequences of climate change is the also increase in the severity, frequency and length of droughts appearing in Europe. The effects of meteorological drought are often substantial, not only for the natural environment but also for humans. Hence, the main purpose of this research was to determine the trends in the severity and occurrence of droughts in Europe during the period 1951–2015 using the standardized precipitation index and the standardized precipitation and evapotranspiration index (SPEI). For six European sites located in mid latitudes, the number of dry months was determined and the trend of their occurrence was examined. Moreover, for the summer months in which the indicators fell below 0, the trend related to the severity of the drought was determined for each site. Despite the absence of a statistically significant trend of an increase in the occurrence of dry months in general, an increase in the severity of droughts occurring in summer was obse...
Long‐term variability and trends in meteorological droughts in Western Europe (1851–2018)
International Journal of Climatology, 2020
We analyzed long-term variability and trends in meteorological droughts across Western Europe using the Standardized Precipitation Index (SPI). Precipitation data from 199 stations spanning the period 1851-2018 were employed, following homogenisation, to derive SPI-3 and SPI-12 series for each station, together with indices on drought duration and severity. Results reveal a general absence of statistically significant long-term trends in the study domain, with the exception of significant trends at some stations, generally covering short periods. The largest decreasing trends in SPI-3 (i.e. increasing drought conditions) were found for summer in the British and Irish Isles. In general, drought episodes experienced in the last two or three decades have precedents during the last 170 years, emphasising the importance of long records for assessing change. The main characteristic of drought variability in Western Europe is its strong spatial diversity, with regions exhibiting a homogeneous temporal evolution. Notably, the temporal variability of drought in Western Europe is more dominant than long-term trends. This suggests that long-term drought trends cannot be confirmed in Western Europe using precipitation records alone. This study provides a long-term regional assessment of drought variability in Western Europe, which can contribute to better understanding of regional climate change during the past two centuries.
Observed drought and wetness trends in Europe: an update
Linear and nonlinear trends of drought and wetness are analysed in terms of the gridded Standardized Precipitation Index (SPI) determined from monthly precipitation in Europe (NCEP/NCAR). In characterizing the meteorological and hydrological aspects, the index is computed on a seasonal and on a bi-annual time scale. Two datasets are compared: one from 1949 to 1997 and the other one includes the update of the last decade (to February 2009). The following results are noted: (i) time series of drought and wetness area coverage (number of grid points above/below the severity threshold) show a remarkable linear trend until about the end of the last century, which is reversed in the last (update) decade. This recent trend reversal is an indication of a nonlinear trend, which is more pronounced on the hydrological time scale. (ii) A nonlinear trend analysis is performed based on the time series of the principal component (PC) associated to the first spatial SPI-eigenvector after embedding it in a time delay coordinate system using a sliding window of 70 months (singular spectrum analysis). Nonlinearity appears as a clear feature on the hydrological time scale. (iii) The first spatial EOF-patterns of the shorter and the longer (updated) SPI time series fields show similar structure. An inspection of the SPI time behaviour at selected grid points illustrates the spatial variability of the detected trends.
Long‐term changes in drought indices in eastern and central Europe
International Journal of Climatology, 2021
This study analyses long-term changes in drought indices (Standardised Precipitation Index-SPI, Standardised Precipitation-Evapotranspiration Index-SPEI) at 1 and 3 months scales at 182 stations in 11 central and eastern European countries during 1949-2018. For comparative purposes, the necessary atmospheric evaporative demand (AED) to obtain SPEI was calculated
Journal of Climate, 2015
Quantification of large-scale climate drivers of drought is necessary to understand better and manage these spatially extensive and often prolonged natural hazards. Here, this issue is advanced at the continental scale for Europe. Drought events are identified using two indices—the 6-month cumulative standardized precipitation and standardized precipitation evapotranspiration indices (SPI-6 and SPEI-6, respectively)—both calculated using the gridded Water and Global Change (WATCH) Forcing Dataset for 1958–2001. Correlation of monthly time series of the percentage of European area in drought with geopotential height for 1958–2001 indicates that a weakening of the prevailing westerly circulation is associated with drought onset. Such conditions are linked to variations in the eastern Atlantic/western Russia (EA/WR) and North Atlantic Oscillation (NAO) atmospheric circulation patterns. Event-based analysis of the most widespread European droughts reveals that a higher number are identi...
Hydrological Processes, 2011
Links between severe hydrological droughts and weather types (WTs) were explored to improve the understanding of hydroclimatological processes involved in the development of regional hydrological drought in north-western Europe. A new Regional Drought Area Index (RDAI) was developed, using daily streamflow, to represent the drought-affected area. Daily RDAI series were created for two regions with homogeneous drought behaviour in Denmark and four regions in Great Britain. An objective version of the Hess-Brezowsky Grosswetterlagen yielding 29 WTs was used. Regional drought characteristics, including duration and frequency, were found to vary considerably between regions. However, in 1976 and 1996, all regions experienced severe events, and these years were found to be the most severe drought years across the study region as a whole. The hydrological response time (i.e. the time over which WTs influence drought development) was found to vary markedly (45-210 days) between regions according to basin storage properties. WT-frequency anomalies (FAs) before and during the onset of the five most severe droughts were identified for each region. The dominant drought-yielding WTs changed between regions and between events within each region. High-pressure systems centred over the respective region were most frequently associated with droughts as well as WTs with a northern (N, NE or NW) or a southern (S, SE or SW) airflow over the Danish and British regions. Five of the six WTs associated with drought for all regions represented a northern high-pressure system (i.e. over Great Britain, Fennoscandia or the Norwegian Sea). This article demonstrates (1) hydrological response time to be fundamental in moderating drought response to mesoscale climatic drivers and (2) severe hydrological droughts may be caused by a complex set of hydroclimatological processes that vary between regions and events.
Multi-Index Drought Assessment in Europe
Proceedings of 3rd International Electronic Conference on Water Sciences (ECWS-3)
Any attempt for the application of integrated drought management requires identifying and characterizing the event, per se. The questions of scale, boundary, and of geographic areal extent are of central concern for any efforts of drought assessment, impact identification, and thus, of drought mitigation implementation mechanisms. The use of drought indices, such as Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), has often led to pragmatic realization of drought duration, magnitude, and spatial extension. The current effort presents the implementation of SPI and SPEI on a Pan-European scale and it is evaluated using existing precipitation and temperature data. The ENSEMBLES Observations gridded dataset (E-OBS) for precipitation, minimum temperature, and maximum temperature used covered the period 1969-2018. The two indices estimated for time steps of 6 and 12 months. The results for the application period of recurrent droughts indicate the potential that both indices offer for an improvement on drought critical areas of identification, threshold definitions and comparability, and towards contingency planning, leading to better mitigation efforts.
The biggest drought events in Europe from 1950 to 2012
Journal of Hydrology: Regional Studies, 2015
Study region: Europe, including European Russia, but excluding Greenland, the Canary Islands, the Azores, and Madeira. Study focus: Drought is a complex climate-related phenomenon that can affect different sectors causing economic, social, and environmental impacts. We focus on meteorological and hydrological droughts, defined as shortage of precipitation over several months and we discuss the biggest drought events in 1950-2012. To define such drought events we computed three drought indicators, the Standardized Precipitation Index, the Standardized Precipitation Evapotranspiration Index, and the Reconnaissance Drought Index and we merged them into a combined indicator at 3-month scale for meteorological and 12-month for hydrological droughts. The indicators have been calculated using the E-OBS gridded data (0.25 • × 0.25 • ). New hydrological insights for the region: Europe has been subdivided into thirteen regions and for each region we determined a list of drought events. The events have been characterized by the time, duration, severity, average area involved, peak month, and area involved at the peak month. We computed time series of the combined indicators for each region and country to determine the twenty-two biggest drought events in 1950-2012. Northern Europe and Russia show the highest drought frequency, duration, and severity in the