| Summary: | Thesis (Ph.D.)--University of Washington, 2018 Blowing briny snow and frost flowers have been suggested as important sources of sea salt aerosols (SSA) over sea ice covered regions, where they can affect radiation, cloud formation, and boundary layer chemistry. During polar spring, observations show periodic near total ozone depletion events (ODEs) in the boundary layer. These ODEs are initiated by the release of reactive bromine gases, however the origin of the reactive bromine has been subject to debate. In particular, saline surface snow, blowing snow SSA and frost flowers SSA have been proposed as potential sources releasing bromine. My Ph.D. research aims to provide new constraints on blowing snow and frost flower sources of SSA and assess their impact on tropospheric chemistry by using satellite observations together with a chemical transport model (CTM). In the first part of my Ph.D. project (Chapter 2), I interpreted observations of aerosol extinction coefficients from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument onboard the Cloud-Aerosol Lidar and Intrared Pathfinder Satellite Observations (CALIPSO) with the GEOS-Chem CTM to evaluate the role of sea ice sources of SSA in the Arctic and Antarctic boundary layer. I find that the inclusion of blowing snow SSA emissions is necessary for the GEOS-Chem model to reproduce the CALIOP aerosol extinctions over sea ice regions during cold months, but that frost flower SSA fail to do so. Using the CALIOP aerosol extinction coefficients, I derived monthly-varying surface snow salinities, which further improves the performance of the blowing snow GEOS-Chem simulation. In the second part of my Ph.D. project (Chapter 3), I implemented bromine release from SSA generated via blowing snow events, and evaluated the model against tropospheric BrO columns retrieved from the Second Global Ozone Monitoring Experiment (GOME-2) onboard the MetOp-A satellite and the Ozone Monitoring Instrument (OMI) onboard the Aura satellite, as well as in-situ ...
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