Development and utilization of hexacopter unmanned aerial vehicle platform to characterize vertical distribution of boundary layer ozone in wintertime

Özet

Vertical observations of ozone play vital roles in understanding various atmospheric chemical processes in theboundary layer, particularly in winter. In this study, we attempted to measure vertical profiles of boundary layerozone in the winter of 2018 over the Yangtze River Delta region of China, using a hexacopter unmanned aerialvehicle (UAV) platform. A commercial portable ozone monitor mounted in a thermal insulation box was attached to the UAV platform to conduct vertical ozone measurements. The results showed that the UAV platformcould effectively capture the vertical variations of boundary layer ozone in wintertime. During the field campaign, surface ozone was in relatively low levels due to weak photochemical production. In the daytime, theozone was well mixed within the boundary layer. At nighttime, uniform vertical distribution patterns andstratified distribution patterns were frequently obtained in ozone profiles below 500 m. Backward trajectoriesand wind profiles were used to investigate the horizontal and vertical transport of ozone. The stratified distribution patterns of ozone were closely associated with strong contemporary advection transport of ozone thatwas accompanied by enhanced winds aloft. Besides, strong wind shear enhanced the downward transport ofozone from the free troposphere into the boundary layer, leading to uniform vertical distribution patterns ofboundary layer ozone and the elevated nocturnal surface ozone levels. The results of this study could provideinsights into the understanding of the spatial variations and evolution patterns of boundary layer ozone inwintertime and constructing suitable boundary layer schemes in atmospheric chemical models.