Quantifying the contribution of thermally driven recirculation to a high-ozone event along the Colorado Front Range using lidar
Loading...
Author/Creator ORCID
Date
2016-08-23
Type of Work
Department
Program
Citation of Original Publication
Sullivan, John T., Thomas J. McGee, Andrew O. Langford, Raul J. Alvarez II, Christoph J. Senff, Patrick J. Reddy, Anne M. Thompson, et al. “Quantifying the Contribution of Thermally Driven Recirculation to a High-Ozone Event along the Colorado Front Range Using Lidar.” Journal of Geophysical Research: Atmospheres 121, no. 17 (2016): 10,377-10,390. https://doi.org/10.1002/2016JD025229.
Rights
This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
Public Domain
Public Domain
Abstract
A high-ozone (O₃) pollution episode was observed on 22 July 2014 during the concurrent “Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality” (DISCOVER-AQ) and “Front Range Air Pollution and Photochemistry Experiment” (FRAPPE) campaigns in northern Colorado. Surface O₃ monitors at three regulatory sites exceeded the Environmental Protection Agency (EPA) 2008 National Ambient Air Quality Standard (NAAQS) daily maximum 8 h average (MDA8) of 75 ppbv. To further characterize the polluted air mass and assess transport throughout the event, measurements are presented from O₃ and wind profilers, O₃-sondes, aircraft, and surface-monitoring sites. Observations indicate that thermally driven upslope flow was established throughout the Colorado Front Range during the pollution episode. As the thermally driven flow persisted throughout the day, O₃ concentrations increased and affected high-elevation Rocky Mountain sites. These observations, coupled with modeling analyses, demonstrate a westerly return flow of polluted air aloft, indicating that the mountain-plains solenoid circulation was established and impacted surface conditions within the Front Range.