Dynamics of upstream-downstream drought characteristics in mountainous regions in current and future climates

During the past years communities on the northern and southern side of the European Alps have experienced winter precipitation and/or snow deficits. These deficits paired with consecutive spring deficits increase the likelihood of summer hydrological droughts in the lower elevation downstream catchments leading to severe impacts. A very prominent example of such a summer hydrological drought related to winter precipitation deficits was the 2022 Po catchment drought. Such droughts have severe impacts on different sectors downstream including agriculture, industry, energy, and the municipal water supply, because of their reliance on water resources provided by the upstream catchments.

Droughts are rare by definition and hence require large datasets to robustly quantify any changes in their characteristics and dynamics (i.e., frequency and intensity), as well as to disentangle the response to climate change from internal climate variability. Therefore, this project will utilize multiple Single Model Initial conditioned Large Ensembles (SMILEs) alongside observational and reanalysis datasets to enhance our understanding of the probability of spatially and temporally compounding winter droughts in upstream catchments followed by consecutive summer droughts in downstream catchments.

The regional focus will be the European Alps, but other mountainous regions with important upstream-downstream dependencies will be analyzed in a later stage.