Background information

Background Information

The Meteorological Drought Duration index is relevant to a wide range of water-related sectors, especially agriculture, forestry, hydrology and water management. This Index is based on daily precipitation and is part of the Drought Hazard type of the Wet and Dry category of the classification.

The index gives the total number of months in a year that experience drought conditions as determined by anomalously low precipitation values based on the 3-month Standardised Precipitation Index (SPI-3). SPI-3 accounts for the deficit (or surplus) of precipitation accumulated over 3 months with respect to the corresponding reference value from a 30-year baseline historical period, here 1981-2010. A higher/lower value indicates shorter/longer droughts durations.

Definition

The count of months in a year with anomalously low precipitation conditions based on the 3-month Standardised Precipitation Index (SPI-3) relative to a reference period, here 1981-2010 (month). A drought event starts when SPI-3 values fall below -1 for at least two consecutive months and ends when the index returns positive.

Data Sources

The data was assembled on behalf of the Copernicus Climate Change Service (C3S) based on climate projections hosted on the C3S Climate Data Store (CDS). The Index is calculated from a set of nine bias-corrected multi-model simulations from the EURO-CORDEX experiment. These simulations have a spatial resolution of 0.25° x 0.25°, a 3-hourly output, and cover scenarios RCP4.5 and RCP8.5. More information about the dataset can be found in the corresponding CDS documentation resources.

Supporting Information

Further information about this application can be found in the ECDE application User Guide and the Data and datasets underpining the ECDE. Related information also be found in other sections of the EEA site:

  • The Index based interactive EEA report: Wet and dry - Droughts (link).
  • EEA Indicators: Meteorological and hydrological droughts in Europe (link).

Data download

The aggregated data shown on the map can be downloaded as csv files.

The application has an interactive map on the left side with a set of drop down menus to select the regions (NUTS, Transnational regions or Europe Zones), the time span (Year, Season or Month) and the emission scenario (RCP4.5 or RCP8.5). By clicking on the map, a scrolling panel appears on the right side displaying interactive plots corresponding to spatial and temporal averages over the selected region. Hover over the plots to see the values.

Some plots show an uncertainty envelope representing the range of likely values, as defined by the IPCC, based on an ensemble of models (see FAQ).

Content in the European Climate Data Explorer pages is delivered by the Copernicus Climate Change Service (C3S) implemented by ECMWF.

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This translation is generated by eTranslation, a machine translation tool provided by the European Commission.