Trends and drivers of recent summer drying in Switzerland

Abstract The Alpine region recently experienced several dry summers with important and adverse impacts on economy, society ecology. Here, we analyse drought indicators, evapotranspiration meteorological data from point observations, reanalyses regional climate model to assess trends drivers of summer in Switzerland the period 1981–2020. indicators station observations ERA5-Land ERA5 show a tendency towards drier half-years (climatic water balance: −39 mm decade −1 , 0–1 m integrated soil content: −5 −7 ) drying most months March October. Both, increasing (potential evapotranspiration: +21 or +7% K warming; actual +8 +15 non-significant precipitation decrease 17 are identified as roughly equivalent drivers. considerable differences for evapotranspiration, especially summers. is clearly than one ERA5-Land. smallest partly moisture-limited years while highest, still mainly energy-limited scales well temperature (+4% warming). seems better match situ measurements ERA5, but remain. Variability also investigated EURO-CORDEX ensemble. Most simulations considerably underestimate recent warming ensemble shows large possible range changes mean change near zero. precipitation-temperature scaling correlation between interannual time scale mostly overestimated. Our results highlight that analysis Central European evolution its remains challenging data, uncertainties exist reanalyses.