JetLag ERA5 1941-2025 v1.0

The JetLag dataset provides Lagrangian jet-stream diagnostics derived from atmospheric reanalysis data. The dataset is generated using the JetLag algorithm described in Rivoire et al., 2026. JetLag algorithm JetLag identifies jet streams from gridded model output by computing trajectory-based Lagrangian descriptors on isentropic surfaces. Jet axes are identified as maxima in isentropic displacement, capturing the material function of jets in the atmosphere as they meander. This formulation allows robust jet identification in regimes where Eulerian definitions become ambiguous due to meandering or intermittency. Code for JetLag is available at: https://doi.org/10.5281/zenodo.18292587 Jet types included The dataset includes diagnostics for: Subtropical jets (STJ) Polar-front jets (PFJ) Both jet types are diagnosed using the same Lagrangian framework. Available variables The dataset includes: latitude of tje jet axis ('lat', in degrees N) zonal component of the wind at the jet axis ('u', in m/s) meridional component of the wind at the jet axis ('v', in m/s) pressure at the jet axis ('p', in hPa) Data source All diagnostics in this archive are computed from ERA5 reanalysis retrieved from the MARS archive: https://apps.ecmwf.int/data-catalogues/era5/?class=ea. The 6-hourly, potential temperature (levtype=pt) data were used. Intended use The JetLag dataset is intended for studies of large-scale atmospheric dynamics, tracer transport, and jet variability, as well as for reproducibility of analyses and figures in the associated publication. The archived version matches the data used in the reference study.