Ozone and Modeled Stomatal Conductance at a High Elevation Subalpine Site in Southeastern Wyoming 1

Ozone concentrations have been monitored at the Glacier Lakes Ecosystem Experiment Site (GLEES) in the Snowy Range of the Medicine Bow Mountains 55 km west of Laramie, Wyoming, USA. The site is located at 3,186 m elevation in a large subalpine meadow of a mature subalpine forest near timberline. Continuous ozone and meteorological monitoring are a part of the GLEES research to determine the effects of atmospheric deposition on alpine and subalpine ecosystems. Ozone monitoring has shown specific summer and winter diel ozone distribution patterns, typical of remote, rural, high elevation sites. The data show relatively high background ozone concentrations with little diel variation in winter. Stratospheric intrusions contribute to the ground-level ozone concentrations in the spring. Summer ozone patterns show diurnal photochemical peaks and significant night time concentrations suggesting lack of scavenging. The relationship of modeled leaf stomatal conductances, boundary layer conductances, canopy conductances and photosynthesis rates to ambient ozone concentrations and measured ozone flux was examined by using regression analysis. Ozone concentrations were also compared with wind, radiation, temperature, and humidity conditions at the site by using regression analysis. The data provide information on ozone concentration and environmental conditions at a remote, high elevation site typical of many wilderness areas of the western United States.