A33K-0332
Representation of the Bi-modal Distribution of Free Tropospheric Ozone Over the Tropical Western Pacific in CAM-CHEM

Wednesday, 16 December 2015
Poster Hall (Moscone South)
Shawn Honomichl1, Douglas E Kinnison1, J F Lamarque1, Alfonso Saiz-Lopez2, William John Randel1 and Laura Pan1, (1)National Center for Atmospheric Research, Boulder, CO, United States, (2)Spanish National Research Council, Zaragoza, Spain
Abstract:
During the CONTRAST field study, in situ aircraft observations revealed a distinct bi-modal distribution of ozone mixing ratios formed by persistent layers of enhanced of ozone relative to background concentrations in the Western Tropical Pacific middle troposphere during the Northern Hemispheric winter. These enhancements may have a measureable impact on the troposphere’s oxidizing capacity in the tropics, which has a direct effect on the regional climate of the western tropical Pacific Ocean and beyond. In this work, we examine the representation of the bi-modal ozone characteristics in the NCAR chemistry-climate model (CAM-CHEM). We also investigate the controlling mechanisms of the bi-modal ozone distribution combining the model and aircraft observations.