Robustness of future atmospheric circulation changes over the EURO-CORDEX domain

European climate is associated with variability and changes in the mid-latitude atmospheric circulation. In this study, we aim to investigate potential future change in circulation over Europe by using the EURO-CORDEX regional climate projections at 0.11° grid mesh. In particular, we analyze future change in 500-hPa geopotential height (Gph), 500-hPa wind speed and mean sea level pressure (MSLP) addressing different warming levels of 1 °C, 2 °C and 3 °C, respectively. Simple scaling with the global mean temperature change is applied to the regional climate projections for monthly mean 500-hPa Gph and 500-hPa wind speed. Results from the ensemble mean of individual models show a robust increase in 500-hPa Gph and MSLP in winter over Mediterranean and Central Europe, indicating an intensification of anticyclonic circulation. This circulation change emerges robustly in most simulations within the coming decade. There are also enhanced westerlies which transport warm and moist air to the Mediterranean and Central Europe in winter and spring. It is also clear that, models showing different responses to circulation depend very much on the global climate model ensemble member in which they are nested. For all seasons, particularly autumn, the ensemble mean is much more correlated with the end of the century than most of the individual models. In general, the emergence of a scaled pattern appears rather quickly.Tugba Ozturk was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under the programme TUBITAK 2219—International Postdoctoral Research Fellowship. This work also received support by the European Union under the Horizon 2020 Grant Agreement 776613, the EUCP project.Publisher's Versio

Asymmetries in Circulation Anomalies Related to the Phases of the North Atlantic Oscillation on Synoptic Time Scales

The North Atlantic Oscillation (NAO) index is often characterized by independent positive and negative NAO events with a characteristic spatial pattern and a typical lifetime of around 1 week. These events are separated by periods of near-neutral NAO conditions. Here, we challenge this view by showing in reanalysis and observed data that the strength and spatial shape of NAO events depends on the NAO index prior to the window of 1 week and this dependency is most pronounced for negative NAO events. The influence is seen in the mean sea level pressure, and in other important features, including blocking frequency and jet stream characteristics, and also in air surface temperature and precipitation in parts of Europe. This new appreciation is important for efforts to improve methods for subseasonal-to-seasonal predictions of NAO.publishedVersio

An ecosystem-wide reproductive failure with more snow in the Arctic

In summer 2018, many arctic regions experienced unprecedented large amounts of snow. This Perspective article reports the ecological impacts of this extreme event, and shows that the severe snow conditions resulted in an almost complete reproductive failure across the entire ecosystem. The 2018 may be a rare event, but it also offers a gloomy peep into the future.Peer reviewe

Improved Predictions for the Arctic and connections to the Midlatitudes

Several Blue-Action partners attended the 2017 Arctic Circle event http://www.arcticcircle.org/ in Reykjavik, Iceland, October 13-15. These are the sessions we have been contributing to: http://www.blue-action.eu/index.php?id=4011 More information about the event and full programme: http://www.arcticcircle.org/ Keywords: Blue-Action, Blue Growth, Improved Predictions, Arctic, northern hemisphere, weather, climate, Climate Services, business strategy, Climate service innovation, climate-resilience, Arctic business, H2020, climate actio

Reconsidering the Quality and Utility of Downscaling

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