Wildfire influences on the variability and trend of summer surface ozone in the mountainous western United States

Autor(en)
Xiao Lu, Lin Zhang, Xu Yue, Jiachen Zhang, Daniel A. Jaffe, Andreas Stohl, Yuanhong Zhao, Jingyuan Shao
Abstrakt

Increasing wildfire activities in the mountainous western US may present a challenge for the region to attain a recently revised ozone air quality standard in summer. Using current Eulerian chemical transport models to examine the wildfire ozone influences is difficult due to uncertainties in fire emissions, inadequate model chemistry, and resolution. Here we quantify the wildfire influence on the ozone variability, trends, and number of high MDA8 (daily maximum 8ĝ€h average) ozone days over this region in summers (June, July, and August) 1989-2010 using a new approach. We define a fire index using retroplumes (plumes of back-Trajectory particles) computed by a Lagrangian dispersion model (FLEXPART) and develop statistical models based on the fire index and meteorological parameters to interpret MDA8 ozone concentrations measured at 13 Intermountain West surface sites. We show that the statistical models are able to capture the ozone enhancements by wildfires and give results with some features different from the GEOS-Chem Eulerian chemical transport model. Wildfires enhance the Intermountain West regional summer mean MDA8 ozone by 0.3-1.5ĝ€ppbv (daily episodic enhancements reach 10-20ĝ€ppbv at individual sites) with large interannual variability, which are strongly correlated with the total MDA8 ozone. We find large fire impacts on the number of exceedance days; for the 13 CASTNet sites, 31ĝ€% of the summer days with MDA8 ozone exceeding 70ĝ€ppbv would not occur in the absence of wildfires.

Organisation(en)
Institut für Meteorologie und Geophysik
Externe Organisation(en)
Peking University, Chinese Academy of Sciences (CAS), University of Southern California, University of Washington, Bothell, University of Washington, Norwegian Institute for Air Research
Journal
Atmospheric Chemistry and Physics
Band
16
Seiten
14687-14702
Anzahl der Seiten
16
ISSN
1680-7316
DOI
https://doi.org/10.5194/acp-16-14687-2016
Publikationsdatum
11-2016
Peer-reviewed
Ja
ÖFOS 2012
105206 Meteorologie
ASJC Scopus Sachgebiete
Atmospheric Science
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/f62b8e0e-1e13-4197-978e-bc06cef0a1a7