10.1 The Behavior of Global Atmospheric Hydroxyl (OH) and Hydroperoxyl (HO2)

Thursday, 11 January 2018: 8:30 AM
Room 18CD (ACC) (Austin, Texas)
William Brune, Pennsylvania State Univ., University Park, PA; and D. O. Miller and A. Thames

Hydroxyl (OH) and hydroperoxyl (HO2) are two primary oxidants drive changes in atmospheric composition. These oxidants are being measured using the Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS) during the four phases of the Atom mission. For the relatively clean atmosphere encountered during the first two ATom phases, expectations are that measured and modeled OH and HO2 should be in relatively good agreement. Here we present measurements of OH and HO2 and compare them to the calculations of a photochemical box model constrained to the other aircraft measurements. Measured and modeled OH and HO2 generally agree to within uncertainties over a number of important controlling variables, such as altitude, location, nitrogen oxides, and photolysis. However, there are important exceptions, particularly as a function on altitude. Some of these measured-to-modeled differences may be due to heterogeneous uptake of HO2, which has been proposed as an important mechanism for establishing global oxidant abundances. Finally, these measurements will be put into the context of OH and HO2 measurements from previous NASA aircraft campaigns.
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