Spatial and Temporal Distribution of Summer Ozone Near the Great Salt Lake

Gridded analyses of near-surface ozone at 1 km horizontal and hourly temporal resolution over northwestern Utah have been created for the 2015 summer season based on observations collected as part of the 2015 Great Salt Lake Summer Ozone Study. Researchers from Utah universities and the Utah Division of Air Quality examined the distribution of boundary-layer ozone during summer 2015 in the vicinity of Utah's Great Salt Lake. Observations from a dozen state air quality measuring sites in northern Utah were combined with those from a novel mix of sensors available from additional fixed locations as well as vehicles, a light rail car, unmanned aerial vehicles, tethered and free-flying sondes, a paraglider, and a traffic helicopter.

The University of Utah two-dimensional variation analysis (UU2DVAR) system was used to create the gridded analyses from all of the available observations. Hourly background grids were determined from averages of the available observations over land distinct from those over the lake as well as assumptions regarding the variation of ozone with elevation. Sensitivity of the analyses to the assumed background fields as well as observational error have been assessed. The high spatial and temporal resolution gridded analyses help to delineate the spatial heterogeneity and temporal evolution of the distribution of ozone during poor air quality episodes arising from the influence of the Great Salt Lake, including thermally-driven circulations such as lake and land breezes.