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

Abstract

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.

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

“…During this time frame 2 ozonesonde were launched, and the O 3 profiles from these sondes are shown as the vertical inserts with surface O 3 data also plotted. Spatially co-located ozonesonde and sUAS O 3 results generally agree well (15%) with the lidar data (Farris et al, 2018), although there was only one set of ozonesonde data for comparison with LMOL data per 200 m height, due to the sensor time constant and ascent rate of the balloon.…”

“…The smaller diameter receiver was used for the first time during OWLETS to provide enhanced measurement capability in near-surface (0.1-1 km altitude) signal range. This set up has been validated against ozonedondes and sUAS in-situ data; a more detailed description of the systems and its performances is found in Farris et al (2018). The fiber outputs from the near-field and far-field telescopes were coupled to collimating optics, UV bandpass filters (280-295 nm spectral window) that were integrated with Hamamatsu photo-multiplier tube (PMT) detectors in light-tight enclosures.…”

Vertical Profiles of Ozone Concentrations in the Lower Troposphere Downwind of New York City During LISTOS 2018–2019

“…Both ozonesonde and LMOL measurements at Westport occurred on various days between 12 July and August 30 during LISTOS, operated by personnel from the NASA LaRC. LMOL is part of NASA's Tropospheric Ozone Lidar Network, and is capable of providing profiles of ozone between 0.1 and 12 km (De Young et al., 2017; Farris et al., 2019; Gronoff et al., 2019).…”

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.…”