2025/08/29 by Talia Tamarin‐Brodsky, Nili Harnik, Swinda K. J. Falkena · 1 voice
Earth and Planetary Sciences · #Ocean Waves and Remote Sensing
paper · pdf · doi:10.22541/essoar.175648176.67917852/v1
The atmospheric circulation is often described as a combination of low-frequency variability, such as weather regimes that can persist for weeks, and high-frequency variability, including synoptic systems that shape our daily weather. In the North Atlantic, regimes such as the North Atlantic Oscillation influence the jet stream and affect surface climate. Here we investigate the dynamics governing the interaction between these timescales, and how it is mediated by Rossby Wave Breaking (RWB) events. A simplified equation is derived to explore which processes contribute to RWB through a meridional overturning of high-frequency potential vorticity, providing a dynamical recipe for when and where wave breaking occurs. We show that slowly varying regimes steer the tracks of high-frequency systems, which in turn determine whether the frequency of cyclonic or anticyclonic RWB is enhanced or suppressed. The recurrence of same-type RWB in a similar position can ultimately shape the mean structure of weather regimes. These findings provide a framework for studying predictability on weekly to seasonal timescales and for assessing how midlatitude circulation may respond to climate change.