J. Christopher Doran
Atmospheric Sciences Technical Group
Pacific Northwest National Laboratory
MSIN: K9-30
P.O. Box 999
Richland, WA 99352
509-372-6149
fax 509-372-6168
christopher.doran@pnl.gov

J. D. Fast, and C. M. Berkowitz
Pacific Northwest National Laboratory

The importance of treating the coupled system of chemical and meteorological processes in understanding the causes of spatial and temporal variations in tropospheric concentrations of ozone and other oxidants is increasingly recognized in the atmospheric chemistry community. Building on recent work we have done in this area, we are undertaking a series of investigations to address two questions: 1) how does the recycling of air masses driven by temperature differences, such as those between land and water surfaces or over elevated topography, affect oxidant levels over adjacent areas, and 2) how do ozone precursors that build up in the nighttime stable boundary layer, and ozone and other photochemical reaction products isolated aloft as the turbulence of the daytime mixed layer decays, combine to affect the evolution of ozone concentrations the following day? To answer these questions we are using meteorological and air chemistry data collected in Houston during the summer of 2000 as part of Texas 2000 campaign. We will also be conducting a field experiment in Phoenix during the early summer of 2001 featuring air chemistry measurements at three levels on or near a skyscraper in downtown Phoenix, low-level flights by the G-1 aircraft, and a network of wind profilers, sodars, and balloon-borne sounding systems. The air chemistry in both of these locations is strongly affected by one or more of the boundary-layer meteorological processes listed above. Our analysis will include both conceptual and numerical approaches; the latter will make use of coupled meteorological, chemical, and particle dispersion models.

Some further information, on the planned Phoenix 2001 Air Chemistry Study, can be found in the viewgraphs from a presentation at the Atmospheric Sciences Program Annual Meeting held in February 2001 and the viewgraphs from a presentation at the Atmospheric Sciences Program Annual Meeting held in March 2002.