Background information

Background Information

The Aridity Actual index is relevant to biodiversity, agriculture, forest and water management.

This Index is based on daily precipitation and evapotranspiration and is part of the Aridity Hazard type of the Wet and Dry category of the classification. A higher/lower value indicates reduced/increased soil water availability.

Definition

The ratio between mean annual actual evapotranspiration and mean annual precipitation, generally calculated over a reference period of 30 years. Actual evapotranspiration is estimated using hydrological models and, in contrast to potential evapotranspiration, accounts for the limited water content actually available in the soil when estimating the evapotranspiration demand.

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 data is from a set of 30-year statistics from two hydrological models forced by eight bias-corrected multi-model simulations from the EURO-CORDEX experiment. The hydrological models are from the Swedish Meteorological and Hydrological Institute (SMHI, E-HYPE model) and Wageningen University (VIC-WUR model). The hydrological simulations have a 5km x 5km resolution 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. More information can also be found on other sections of the EEA site:

  • The Index based interactive EEA report: Wet and dry - Aridity (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), the emission scenario (RCP4.5 or RCP8.5) and the hydrological model (SMHI’s E-HYPE or Wageningen University’s VIC-WUR). By clicking on the map, a panel appears on the right side displaying an interactive plot corresponding to spatial and temporal averages over the selected region. Hover over the plot to see the values.

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.