title: Impact of increasing heat waves on U.S. ozone episodes in the 2050s: Results from a multimodel analysis using extreme value theory.
abstract: We develop a statistical model using extreme value theory to estimate the 2000-2050 changes in ozone episodes across the United States. We model the relationships between daily maximum temperature (Tmax) and maximum daily 8-hour average (MDA8) ozone in May-September over 2003-2012 using a Point Process (PP) model. At ~20% of the sites, a marked decrease in the ozone-temperature slope occurs at high temperatures, defined as ozone suppression. The PP model sometimes fails to capture ozone-Tmaxrelationships, and so we refit the ozone-Tmaxslope using logistic regression and a Generalized Pareto Distribution model. We then apply the resulting hybrid-EVT model to projections ofTmaxfrom an ensemble of downscaled climate models. Assuming constant anthropogenic emissions at the present level, we find an average increase of 2.3 days a-1in ozone episodes (> 75 ppbv) across the United States by the 2050s, with a change of +3-9 days a-1at many sites.
authors.affiliation: School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA.
authors.forename: L
authors.initials: L
authors.lastname: Shen
authors.affiliation: School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA.
authors.forename: L J
authors.initials: LJ
authors.lastname: Mickley
authors.affiliation: Research Applications Laboratory, National Center for Atmospheric Research, Boulder, Colorado, USA.
authors.forename: E
authors.initials: E
authors.lastname: Gilleland