Reanalysis-driven simulations may overestimate persistent contrail formation by 100%–250%

Abstract Model-based estimates of aviation’s climate impacts have found that contrails contribute 36%–81% instantaneous radiative forcing. These depend on the accuracy meteorological data provided by reanalyses like ECMWF Reanalysis 5th Generation (ERA5) and Modern Era Retrospective analysis for Research Applications V2 (MERRA-2). Using from 793 044 radiosondes, we find persistent forming at cruise altitudes in 30° N–60° S are overestimated factors 2.0 3.5 ERA5 MERRA-2, respectively. Seasonal inter-annual trends well-reproduced both models (R 2 = 0.79 0.74). We also a contrail lifetime metric is 17% 45% MERRA-2. Finally, incorrectly identify individual regions could form 87% 52% time, results suggest currently overestimate number contrails. Additional observations needed future order to provide locally accurate or support mitigation strategies.