A climatology of North Atlantic extratropical cyclones using piecewise potential vorticity inversion

There are still considerable uncertainties surrounding the frequency and characteristics of extratropical cyclones within climate model projections. Some of the uncertainty may originate from considering all cyclones together rather than examining dynamically distinct groups of cyclones. Here we present a preliminary climatology of wintertime cyclones across the North Atlantic created using piecewise potential vorticity inversion. Cyclones are identified using the Hodges (1999) TRACK methodology on ERA5 reanalysis data from December–February and from 1979–2024 across the North Atlantic basin. We apply the piecewise potential vorticity inversion method to these cyclone tracks to determine whether an individual cyclone strengthens most from upper-, middle-, or lower-troposphere potential vorticity anomalies. Cyclones are analyzed to assess how their structure, development, and large-scale flow characteristics differ between the three classes of cyclones. We aim to perform similar analysis for cyclones in climate model runs of both current and future climate states to assess the biases and projected changes to the different groups of extratropical cyclones.