High-resolution quasi-idealized experiments for future and present-day based upon composites from a decades-long set of recurving landfalling (RCL) North Atlantic ET cases

We present a high-resolution quasi-idealized experiment based upon composites from a decades-long set of recurving landfalling (RCL) North Atlantic extratropical transition (ET) cases. Following Jung and Lackmann (2021), we apply the track-based classification method of Colbert and Soden (2012) to the historical database (1979 to 2018) of North Atlantic RCL ET events; recurving landfalling tropical cyclones (TCs) are defined as those which cross 70°W north of 25°N or cross 65W north of 40N and threaten the U.S. East Coast. We use the Atlantic Hurricane Database (HURDAT2) best-track data (Landsea and Franklin 2013); the track-based classification procedure yields 37 RCL ET cases over the 40-year period. To minimize the spread of the selected ET cases in terms of time to complete transition, we apply a threshold of 36 h as in Jung and Lackmann (2021). As HURDAT2 only specifies when transition is complete but does not provide the timeline of the transition, we supplement it with the cyclone phase space (CPS) method of Hart (2003) to diagnose onset and completion times of ET; ET events are first identified by HURDAT2 and then we compute the CPS parameters to confirm the ET timeline for each event using the ERA5 reanalysis dataset (Hersbach et al. 2020). This filtering process yields 21 RCL ET cases. This dataset is initialized by randomized 15-case composites selected from the 21 RCL ET cases as in Jung and Lackmann (2021). This dataset was used to produce figures and tables in the manuscript of Jung and Lackmann (2023, in review). 

Due to storage limitations, the full dataset is much too large to be published (~ 500GB). Instead, a subset consisting of 3-hourly atmospheric temperature at 17 vertical levels, zonal and meridional wind at 17 vertical levels, 3 hourly accumulated precipitation, mean sea level pressure, 10-m zonal and meridional wind, sea surface temperature, and relative humidity at 17 vertical levels is presented. If you wish to access the full dataset, please contact one of the authors.