Search for: All records

Abstract. Ozone is a pollutant formed in the atmosphere by photochemical processes involving nitrogen oxides (NOx) and volatile organic compounds (VOCs) when exposed to sunlight. Tropospheric boundary layer ozone is regularly measured at ground stations and sampled infrequently through balloon, lidar, and crewed aircraft platforms, which have demonstrated characteristic patterns with altitude. Here, to better resolve vertical profiles of ozone within the atmospheric boundary layer, we developed and evaluated an uncrewed aircraft system (UAS) platform for measuring ozone and meteorological parameters of temperature, pressure, and humidity. To evaluate this approach, a UAS was flown with a portable ozone monitor and a meteorological temperature and humidity sensor to compare to tall tower measurements in northern Wisconsin. In June 2020, as a part of the WiscoDISCO20 campaign, a DJI M600 hexacopter UAS was flown with the same sensors to measure Lake Michigan shoreline ozone concentrations. This latter UAS experiment revealed a low-altitude structure in ozone concentrations in a shoreline environment showing the highest ozone at altitudes from 20–100 m a.g.l. These first such measurements of low-altitude ozone via a UAS in the Great Lakes region revealed a very shallow layer of ozone-rich air lying above the surface. 

The lake breeze circulation along Lake Michigan is associated with high tropospheric ozone concentrations at shoreline locations. The 2021 Wisconsin's Dynamic Influence of Shoreline Circulation on Ozone (WiscoDISCO-21) campaign involved atmospheric measurements over Chiwaukee Prairie State Natural Area in Southeastern Wisconsin from May 21–26, 2021. Three different platforms, two uncrewed aerial systems (UAS) and a Doppler lidar instrument, were used to collect data on this campaign, supplemented by a ground-based Wisconsin DNR maintained regulatory monitor at the site. A Purdue University M210 multirotor copter, and the University of Colorado RAAVEN fixed-wing aircraft were flown in coordination. Using data from the ground station, RAAVEN and onsite lidar, lake breezes were detected on several days of the campaign. The longest sustained lake breezes during the campaign were detected on May 22, 2021, from 17:00–21:38 UTC and on May 24, 2021, from 14:24–22:51 UTC. The presence of the lake breezes correlated with detected temperature inversions measured from the RAAVEN and high ozone events measured from the M210. Lake breezes were investigated with their relationship to vertical profiles measured on the UAS, ozone concentrations, and marine boundary layer height observed with Doppler lidar to demonstrate a multi-layered lower atmosphere. A buoyant internal boundary layer was observed over land from 40–100 m AGL below highest ozone concentrations. Marine layer extent was investigated through minimum buoyancy and Richardson number analysis, showing limited vertical mixing at altitudes up to 200 m AGL, below easterly lake breeze circulation patterns extending upward to 400 m AGL in the late day. 

Abstract. The mesoscale meteorology of lake breezes along Lake Michiganimpacts local observations of high-ozone events. Previous manned aircraftand UAS observations have demonstrated non-uniform ozone concentrationswithin and above the marine layer over water and within shorelineenvironments. During the 2021 Wisconsin's Dynamic Influence of ShorelineCirculations on Ozone (WiscoDISCO-21) campaign, two UAS platforms, afixed-wing (University of Colorado RAAVEN) and a multirotor (PurdueUniversity DJI M210), were used simultaneously to capture lake breeze duringforecasted high-ozone events at Chiwaukee Prairie State Natural Area insoutheastern Wisconsin from 21–26 May 2021​​​​​​​. The RAAVEN platform (data DOI:https://doi.org/10.5281/zenodo.5142491, de Boer et al., 2021) measured temperature, humidity, and 3-D winds during2 h flights following two separate flight patterns up to three times per dayat altitudes reaching 500 m above ground level (a.g.l.). The M210 platform (data DOI: https://doi.org/10.5281/zenodo.5160346, Cleary et al., 2021a) measured vertical profiles of temperature, humidity,and ozone during 15 min flights up to six times per day at altitudesreaching 120 ma.g.l. near a Wisconsin DNR ground monitoringstation (AIRS ID: 55-059-0019). This campaign was conducted in conjunctionwith the Enhanced Ozone Monitoring plan from the Wisconsin DNR that included Dopplerlidar wind profiler observations at the site (dataDOI: https://doi.org/10.5281/zenodo.5213039, Cleary et al., 2021b).