Projected changes in precipitation variability over Europe in CMIP6 climate models

Changes in the amount, intensity, frequency and type of precipitation are observed in some places over recent decades (IPCC 2021). While much effort has been devoted to analyzing long-term changes in mean values and extremes, studies on changes in precipitation variability have been rather scarce. Long-term changes in climate variability are, nevertheless, an important aspect of the climate change with various impacts on society and environment. Therefore it is necessary to know whether and how the precipitation variability will change in the future. To this end, it is important that it is simulated correctly by recent climate models. In our study, we analyze outputs from an ensemble of different CMIP6 global climate models and several reanalyses and gridded observed datasets. We study long-term changes in day-to-day precipitation variability and how they differ between various datasets for the historical and current climate. We evaluate how successful the climate models are in reproducing precipitation variability, while identifying biases and errors common to all models or to groups of models. We analyze projected changes of short-term precipitation variability in model simulations over the whole 21st century. We focus on the North Atlantic-European sector. We consider wet-to-wet and dry-to-dry transition probabilities as a measure of short-term precipitation variability, focusing on winter and summer seasons separately. Ref.: IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)].