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

Abstract

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.

Demonstration of an off-axis parabolic receiver for near-range retrieval of lidar ozone profiles

“…5 time series suggests rapidly changing significant small-scale gradients, making the UAV and lidar co-comparison more challenging than anticipated. The near-surface variability is attributed, in part, to large shipping lane traffic adjacent to the CBBT site as well as other factors, documented in Gronoff et al (2018), where large changes in Pandora columnar NO 2 correlated with lidar near-surface ozone titration events. Furthermore, the signal closest in range has the greatest potential for instrumental error, and limited height range of the UAV may have revealed an increased error for the lowest few recoverable range bins < 200 m, and suggests the need for further investigation.…”

“…Figure 3 displays the 32 h data taken by the near-range OAP receiver, overlaid with the ozonesonde, UAV and surface in situ ozone measurements taken in the 1-2 August time frame. The vertical resolution of the lidar data changes with altitude by an adaptive smoothing technique that is described in work detailing a titration event captured during the OWLETS campaign (Gronoff et al, 2018). Data collection started at approximately 08:00 local time on 1 August, with surface and near-surface ozone increasing in magnitude as the day progressed.…”

Evaluation of NASA's high-resolution global composition simulations: Understanding a pollution event in the Chesapeake Bay during the summer 2017 OWLETS campaign

“…1) using two Tropospheric Ozone LiDAR Network (TOLNet) LiDARs (Sullivan et al, 2016a,Sullivan et al, 2016bSenff et al, 2016) to provide more information on the water-land transition. The NASA LaRC Mobile Ozone LiDAR [LMOL] (Farris et al, 2019;Gronoff et al, 2019) was stationed at CBBT and the NASA Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar [GSFC TROPOZ DIAL] (Sullivan et al, 2014) was stationed at LaRC. The LiDAR data is retrieved at a 5-min temporal resolution.…”

“…Two main research sites were selected to represent the water-land gradient (see Fig. 1) during OWLETS: 1) on top of the third island of the Chesapeake Bay Bridge Tunnel (CBBT) (Gronoff et al, 2019) served as the direct over water site; and 2) NASA Langley Research Center (LaRC) served as the over land (continental) site. We focus on a high ozone episode from July 19 th to 21 st .…”

Evaluation of UV Aerosol Retrievals from an Ozone Lidar

“…Some ozone lidars have an aerosol channel available, either independently or sharing receiving optics with the ozone channel (e.g., Browell et al, 1994;De Young et al, 2017;Gronoff et al, 2019;Kovalev and McElroy, 1994;Uchino and Tabata, 1991). For most of the traditional two-wavelength ozone lidars without an aerosol channel, although the aerosol retrieval algorithm has been discussed in a few literatures (e.g., Eisele and Trickl, 2005;Langford et al, 2019;Papayannis et al, 1999;Sullivan et al, 2014), the evaluation of the aerosol retrieval product and its error budget have rarely been addressed.…”