Trajectory hunting for linking stratospheric aerosol extinction measurements: validation with OSIRIS and application to the 2022 Hunga Tonga eruption

Trajectory hunting is a Lagrangian, transport-based technique that links atmospheric observations along calculated air-parcel pathways to enable consistency checks and to contribute to validation and data comparison studies. By connecting independent observations across space and time, trajectory hunting increases the number of coincidences available for comparison and thus reduces uncertainty in studies limited by sparse availability of direct matches. In this study, we assess the use of trajectory hunting for stratospheric aerosol extinction measurements based on observations from the Optical Spectrograph and InfraRed Imaging System (OSIRIS). Trajectories computed with HYSPLIT and FLEXPART are used to connect independent OSIRIS aerosol extinction profiles along transport pathways, enabling self-consistency tests under various stratospheric conditions. In addition, using the 2022 Hunga Tonga eruption as a case study, we apply trajectory hunting to assess volcanic plume transport by mapping plume evolution and age along simulated dispersion pathways, and to compare these against spaceborne observations to evaluate the consistency of trajectory hunting during periods of strong stratospheric perturbation. These results will demonstrate the potential of using trajectory hunting to support validation of stratospheric aerosol products and to provide observationally constrained insights into aerosol transport and evolution, with implications for future applications to the High-Altitude Aerosols, Water Vapour, and Clouds (HAWC) mission and multi-sensor stratospheric aerosol datasets.