EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Transitions between dry and wet periods in Europe during 1950–2019

Zuzana Bestakova1,2, Petr Maca2, Jan Kysely1,2, Ujjwal Singh2, Yannis Markonis2, and Martin Hanel2
Zuzana Bestakova et al.
  • 1Institute of Atmospheric Physics CAS, Department of Climatology, Praha, Czechia (
  • 2Faculty of Environmental Sciences, Czech University of Life Sciences, Prague, Czech republic (

The study deals with probabilities of transitions from arid to humid environment and vice versa in
Europe. Aridity index, defined as a ratio of potential evapotranspiration and precipitation and
representing the ratio between energy availability and water availability, is used to characterize humid
(wet) and arid (dry) regions and allows us to study transitions between individual periods (wet-wet,
wet-dry, dry-dry, dry-wet). Three gridded datasets – CRU (UEA, 2020), E-OBS (ECAD, 2020) and ERA5
(ECMWF, 2020) – are used for this purpose. The aim of the study is to compare the three datasets as
to transitions between wet and dry conditions, which are determined according to the aridity index,
and evaluate the variability in Europe over 1950–2019. The changes in the aridity index since 1950 are
found to be most pronounced in Northern and Central Europe.

ECAD, 2020: E-OBS gridded dataset, available from
UEA, 2020: University of East Anglia – Climatic Research Unit, available from
ECMWF, 2020: European Centre for Medium-Range Weather Forecasts – ERA5, available from

How to cite: Bestakova, Z., Maca, P., Kysely, J., Singh, U., Markonis, Y., and Hanel, M.: Transitions between dry and wet periods in Europe during 1950–2019, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9951,, 2021.

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