The three-way feedback between Rossby wave breaking events, circulation regimes, and surface weather

Rossby Wave Breaking (RWB) events describe the last stage in the life cycle of baroclinic atmospheric disturbances. These breaking events can strongly influence the large-scale circulation and are tightly related to low-frequency weather regimes. In addition, RWBs are often associated with weather extremes such as heat waves, blockings, and extreme precipitation events. Here we examine the three-way interaction between RWB, weather regimes, and surface weather in the North Atlantic. This is done by combining a RWB detection algorithm, a storm-tracking routine, and a clustering technique to identify low-frequency circulation regimes in the North-Atlantic. We show that the surface storm characteristics are significantly altered with the weather regime, with distinct and clearly preferred storm paths in each cluster. These largely follow the selective absorption mechanism proposed initially for the maintenance of blocking. We suggest a picture in which the resulting RWB frequencies and positions in each cluster are modified by the corresponding tracks of cyclones and anticyclones, with the maximum breaking found where there is a constructive interaction with the low-frequency flow. The positions of RWBs, in turn, shape the overall cluster structure and contributes to the persistence of the weather regime. An improved understanding of the relation between weather systems, RWB events, and weather regimes can also help us improve our understanding of and confidence in projected future circulation changes (e.g., by relating changes in the frequency and positions of RWB events, storm-tracks, and the North-Atlantic jet).