Ventilated potential intensity (vPI) and ventilated genesis potential index (GPIv) from ERA5 and MERRA-2, 2° global monthly

Global monthly fields of the tropical cyclone ventilated potential intensity (vPI), the ventilated genesis potential index (GPIv) and all of their components (potential intensity, ventilation index, vertical wind shear, entropy deficit, capped absolute vorticity, SST) on a 2° grid, computed from two reanalyses with the Python package tcpyVPI v1.4.3 using the default (published) parameters of Chavas, Camargo & Tippett (2025, J. Climate). ERA5: 1940-01 to 2026-09 (2026-07 to 2026-09 are preliminary ERA5T), one netCDF file per year. MERRA-2: 1980-01 to 2026-08, one netCDF file per year. Inputs are conservatively averaged to 2° before computing, so GPIv is on its 2° calibration grid. Over ocean, vPI and GPIv are 0 wherever no storm can be supported (ventilation index above 0.145, or zero potential intensity, including SST ≤ 5 °C); they are undefined (NaN) over land. Two animations of ERA5 vPI are included: the 1991–2020 monthly climatology and the July–October mean of each year, 1940–2025. See README.md for variables, methods and caveats, including the arbitrary absolute scale of GPIv and a step-like rise in PI and GPIv around 1999–2002 in both reanalyses (larger in ERA5). Contains modified Copernicus Climate Change Service information (2026); MERRA-2 data from NASA GMAO via GES DISC. Data licensed CC BY 4.0.