Varying precipitation variability over Europe in observed data and climate models

Since long-term changes in climate variability are an important aspect of climate change, it is necessary to know whether and how they will change in the future. To this end, it is also important that they are simulated correctly by climate models. Despite its importance to the society and relevance in various impacts, short-term precipitation variability was given very little attention even in the last IPCC report. In our analysis, we aim to answer these questions: (1) What long-term changes in day-to-day precipitation variability have been observed? (2) Do the short-term precipitation variability and its long-term trends differ between various datasets, and how much? (3) How successful are climate models in reproducing precipitation variability? Is it possible to identify biases and errors common to all or majority of models, or to groups of models? (4) What changes of short-term precipitation variability do climate models project in future? Are the observed changes consistent with the projected changes, that is, does the anthropogenic climate change already manifest in the recently observed changes of variability?

We analyze day-to-day variability in precipitation in North Atlantic and European sector. We consider wet-to-wet and dry-to-dry transition probabilities as a measure of short-term precipitation variability, focusing on winter (DJF) and summer (JJA) seasons separately. We compare results obtained from stations data, gridded observed data (E-OBS), various reanalyzes, and outputs of an ensemble of CMIP6 global climate models. We analyze historical model runs starting in 1950 and possible climate change over the 21^st century in the simulations under the SSP585 scenarios.