A method for quantifying near range point source induced O₃ titration events using Co-located Lidar and Pandora measurements

Abstract

A ground-based tropospheric O3 lidar with unique vertical near-range capabilities was deployed in support of the larger OWLETS 2017 campaign on the Chesapeake Bay Bridge Tunnel, at the mouth of the Chesapeake Bay. It was sited in close proximity to a shipping channel with an ensemble of additional instrumentation including Pandora spectrometer systems, ozonesonde launches, and in-situ trace gas monitors – one flying on a drone. This unique combination enabled successful observation of a near-surface maritime ship plume emission event on August 01, 2017. The observations demonstrate an NO2 enhancement coincident with O3 depletion in the low altitude range of lidar data, allowing for quantification of ship plume height behavior as well as the evolution of trace-gas concentrations. The technological improvements enabling the observation are presented and discussed, demonstrating that a single observation platform would not have been able to fully capture and contextualize the emission event. This synergistic ground-based sampling approach shows great promise for future verification and validation of satellite air quality and atmospheric composition measurements.