An Analysis of Seacions Ozonesonde Measurements from St. Louis MO: Providing Insight into How Cross Country Wildfires and Descending Stratospheric Air over the Great Plains Impact Regional Air Quality

Abstract:

As part of the SouthEast American Consortium for Intensive Ozone Network Study (SEACIONS) mission, 32 ozonesondes were launched from Forest Park in mid-town St. Louis between 8 Aug and 23 Sept 2013. These launches were supported by concurrent co-located continuous ground level ozone measurements at Saint Louis University’s St. Louis Ozone Garden. During the operation of this site, wildfires from both Idaho’s Beaver Creek (~115K acres) and California’s RIM fire (~258k acres) generated copious amounts of pollution. In addition, widespread agricultural fires in the Midwest were also taking place. To interpret our observations over St. Louis, we used multiple satellite-derived products and retrievals in conjunction with trajectory calculations from the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. We examined a blocking high pressure event [Aug 26-30] which led to ozonesonde profile changes resulting from Stratospheric-Troposphere Exchange (STE) in addition to the smoke from the fires. This case study involved two mixed layer O₃ enhancements, which could be spotted at multiple sites within the SEACIONS ozonesonde network. Our findings illustrate how satellite measurements can be used to assess the contribution of the transport of pollution from various sources to local air quality.