Examining the Oxidative Capacity of the Troposphere in the Remote Tropical Western Pacific Using Measurements from CONTRAST
Julie M Nicely1, Daniel C Anderson1, Timothy P Canty2, Ross J Salawitch3, Glenn Wolfe4, Eric C Apel5, Elliot L Atlas6, Nicola J Blake7, James F Bresch8, Teresa Lynn Campos9, Samuel R Hall10, Thomas F Hanisco4, Cameron R Homeyer11, Shawn Bryan Honomichl12, Rebecca S Hornbrook9, Jorgen B Jensen12, Douglas Edward Kinnison13, J F Lamarque12, Laura Pan14, Daniel D Riemer15, Kirk Ullmann9 and Andrew John Weinheimer16, (1)University of Maryland College Park, College Park, MD, United States, (2)University of Maryland, College Park, Department of Atmospheric and Oceanic Science, College Park, United States, (3)University of Maryland College Park, Department of Chemistry and Biochemistry, College Park, MD, United States, (4)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (5)National Center for Atmospheric Research, Atmospheric Chemistry Observations and Modeling, Boulder, United States, (6)University of Miami, Miami, United States, (7)University of California Irvine, Department of Chemistry, Irvine, United States, (8)National Center for Atmospheric Research (NCAR), Mesoscale & Microscale Meteorology Lab, Boulder, CO, United States, (9)National Center for Atmospheric Research, Atmospheric Chemistry Observations & Modeling Laboratory, Boulder, United States, (10)National Center for Atmospheric Research (NCAR), Atmospheric Chemistry Observations and Modeling Laboratory, Boulder, United States, (11)University of Oklahoma, School of Meteorology, Norman, OK, United States, (12)National Center for Atmospheric Research, Boulder, CO, United States, (13)National Center for Atmospheric Research (NCAR), Atmospheric Chemistry Observations & Modeling Laboratory (ACOM), Boulder,CO, United States, (14)National Center for Atmospheric Research, Atmospheric Chemistry Observations & Modeling, Boulder, United States, (15)University Miami, Miami, FL, United States, (16)National Center for Atmospheric Research, Atmospheric Chemistry Observations and Modeling Laboratory, Boulder, United States
Abstract:
Hydroxyl radical (OH) is the main daytime oxidant in the troposphere and determines the atmospheric lifetimes of many compounds of interest. It has been hypothesized that a region of very low OH in the tropical western Pacific Ocean allows otherwise short-lived compounds (including biogenic ozone depleting substances) to be transported intact to the UTLS by deep convection. We use measurements from the CONTRAST field campaign in the tropical western Pacific to constrain a box model to examine the oxidative capacity of the troposphere in this region. Measurements reveal a background, unpolluted state of the troposphere, with pervasive high O3/low H2O filamentary structures existing in the mid-troposphere; we focus on modeling OH in these distinct chemical environments and investigating the resulting impact on instantaneous lifetimes of species of interest.
