SGER: Surface Deposition and Vertical Transport of Ozone During the Polar Sunrise

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FuentesThe Principal Investigator will conduct research in the Arctic atmospheric boundary layer to gain a better understanding on the processes leading to ozone depletion. The project will be part ol'the Polar Sunrise Experiment-2000 (PSE2000) with three main objectives: To investigate and quatitfy the ozone depletion due to surface (snowpack) bases processes. To define the vertical transport of ozone from the stable marine boundary layer to the underlying snowpack. To specify the ocean to atmosphere exchange of lieat, water vapor and after ozone depletion episodes. During February - May 2000, a series of surface- and airborne-based measurements will be undertaken at two experimental sites, at Alert and Williams Island. The Principal Investigator will attempt for the first time to determine in situ ozone fluxes to the snowpack using the eddy covariance and will test the hypothesis that accumulation of ozone reactive materials on and or inside the snowpack contribute to boundary layer ozone destruction during the Polar sunrise. He surmises that processes occurring within the snowpack may explain important missing details in ozone depletion mechanisms. To verify if the snowpack constitutes a sink for ozone, detailed measurements will be made in the interstitial air within the snowpack. Gas-phase measurements at five depths, from the surface to 100-150 cm, will be achieved through air sampling with chamber systems, coupled with highly sensitive ozone analyzers. During spring Arctic ozone depletion episodes, the atmospheric column extending from the surface to about 300 meters (m) can be devoid of ozone. Above the 300-meter level, the height of the capping inversion of the mixed layer, ozone mixing ratios can exceed 40 ppbv. This ozone reservoir can serve as a source of surface ozone via downward transport by turbulent eddies. Because the Arctic troposphere is dark for several months, the atmospheric boundary layer is stable and stratified, thus preventing atmospheric vertical mixing. Therefore, photochnmically reactive chemical species may accumulate in the boundary layer and become available to partake in reactions when sunlight resumes. He will investigate the role of ocean to atmosphere exchange of energy and momentum on the chemical composition of the boundary layer by defining the individual components of the energy balance for the camp surface. The data set will be used in the development and validation of numerical modeling systems to understand the atmosphere-ocean energy exchange capacity at the ice-camp site, thereby characterizing the availability of activation energy for local chemical reactions.