A ground-based tropospheric O 3 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 monitorsone 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 NO 2 enhancement coincident with O 3 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.

Abstract. During the 2017 Ozone Water Land Environmental Transition Study (OWLETS), the Langley mobile ozone lidar system utilized a new small diameter receiver to improve the retrieval of near-surface signals from 0.1 to 1 km in altitude. This new receiver utilizes a single 90 ∘ fiber-coupled, off-axis parabolic mirror resulting in a compact form that is easy to align. The single reflective surface offers the opportunity to easily expand its use to multiple wavelengths for additional measurement channels such as visible wavelength aerosol measurements. Detailed results compare the performance of the receiver to both ozonesonde and in situ measurements from a UAV platform, validating the performance of the near-surface ozone retrievals. Absolute O3 differences averaged 7 % between lidar and ozonesonde data from 0.1 to 1.0 km and yielded a 2.3 % high bias in the lidar data, well within the uncertainty of the sonde measurements. Conversely, lidar O3 measurements from 0.1 to 0.2 km averaged 10.5 % lower than coincident UAV O3. A more detailed study under more stable atmospheric conditions would be necessary to resolve the residual instrument differences reported in this work. Nevertheless, this unique added capability is a significant improvement allowing for near-surface observation of ozone.

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Abstract. During the 2017 Ozone Water Land Environmental Transition Study (OWLETS), the Langley Mobile Ozone Lidar system utilized a new small diameter receiver to improve the retrieval of near-surface signals from 0.1 to 1 km in altitude. This new receiver utilizes a single 90 degree fiber-coupled, off-axis parabolic mirror resulting in a compact form that is easy to align. The single reflective surface offers the opportunity to easily expand its use to multiple wavelengths for additional measurement channels such as visible wavelength aerosol measurements. This unique added capability allows for near-field analysis of ozone profile concentrations, enabling the study of near-surface pollution dynamics. Results compare the performance of the receiver to both ozonesonde and in-situ measurements from a UAV platform, validating the performance of the near-surface ozone retrievals.

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