Large spread in the representation of compound long-duration dry and hot spells over Europe in CMIP5

Abstract. Long-duration, sub-seasonal dry spells in combination with high temperature extremes during summer have led to extreme impacts on society and ecosystems the past. Such events are expected become more frequent due increasing temperatures as a result of anthropogenic climate change. However, there is little information how long-duration hot represented global models (GCMs). In this study, we evaluate 33 CMIP5 (coupled model intercomparison project 5) GCMs their representation spells. We define spell consecutive number days daily precipitation less than 1 mm. tend underestimate persistence northern Europe, while large variability exists between estimates central southern where contrasting biases. Throughout also find spread Europe related spells, that produce longer higher temperatures, vice versa. Our results indicate differences not internal variability. At latitudes 50–60∘ N, persistent strongly anticyclonic systems, such atmospheric blocking subtropical ridges. Furthermore, simulating frequency systems ERA5 simulate 1.4, 2.8 K warmer lower these areas. Overall, errors large-scale certain parts Europe. This important consider when interpreting plausibility future projections from highlights potential value improvements may for simulation impactful hazards.