EGU22-9324, updated on 28 Mar 2022
https://doi.org/10.5194/egusphere-egu22-9324
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Control of North Atlantic cyclone variability and impacts by the large-scale atmospheric flow

Camille Li1,2, Erica Madonna1,2, Gabriel Hes2,3, Clio Michel1,2, and Peter Y.F. Siew1,2,4
Camille Li et al.
  • 1University of Bergen, Geophysical Institute, Bergen, Norway (camille.li@uib.no)
  • 2Bjerknes Centre for Climate Research, Bergen, Norway
  • 3Départment de Géosciences, École Normale Supérieure, PSL Research University, Paris, France
  • 4Lamont-Doherty Earth Observatory, Columbia University, Palisades, USA

Extratropical cyclones are key players in the poleward transport of moisture and heat. This study investigates wintertime cyclone variability to better understand the large-scale controls on their frequency, path and impacts at higher latitudes. One of the main corridors for Arctic-bound cyclones is through the North Atlantic to the Barents Sea, a region that has experienced the greatest retreat of winter sea ice during the past decades. Large-scale atmospheric conditions are found to be decisive, with the strongest surface warming from cyclones originating south of 60N in the North Atlantic and steered northeastward by the upper-level flow. Atmospheric conditions also control cyclone variability in the Arctic proper: months with many cyclones are characterized by an absence of high-latitude blocking and enhanced local baroclinicity, due to the presence of strong upper-level winds and a southwest-northeast tilted jet stream more than changes in sea ice. Due to the large interannual variability in the number of Arctic-bound cyclones, no robust trends are observed over the last 40 years. Our results highlight the importance of accounting for internal variability of the large-scale atmospheric circulation in studies of long-term changes in extratropical cyclones.

How to cite: Li, C., Madonna, E., Hes, G., Michel, C., and Siew, P. Y. F.: Control of North Atlantic cyclone variability and impacts by the large-scale atmospheric flow, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9324, https://doi.org/10.5194/egusphere-egu22-9324, 2022.