HR: 1330h
AN: A22A-1045    [PDF]
TI: Nitric Acid Uptake on Subtropical Cirrus Cloud Particles
AU: * Popp, P J
EM: ppopp@al.noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, R/AL6, Boulder, CO 80305 United States
AU: * Popp, P J
EM: ppopp@al.noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80305 United States
AU: Gao, R S
EM: gao@al.noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, R/AL6, Boulder, CO 80305 United States
AU: Marcy, T P
EM: tmarcy@al.noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, R/AL6, Boulder, CO 80305 United States
AU: Marcy, T P
EM: tmarcy@al.noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80305 United States
AU: Fahey, D W
EM: fahey@al.noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, R/AL6, Boulder, CO 80305 United States
AU: Fahey, D W
EM: fahey@al.noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80305 United States
AU: Hudson, P K
EM: phudson@al.noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, R/AL6, Boulder, CO 80305 United States
AU: Hudson, P K
EM: phudson@al.noaa.gov
AF: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80305 United States
AU: Thompson, T L
EM: thompson@al.noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, R/AL6, Boulder, CO 80305 United States
AU: Karcher, B
EM: bernd.kaercher@dlr.de
AF: Institute fur Physik der Atmosphare, Deutches Zentrum fur Luft and Raumfahrt, Wessling, 82234 Germany
AU: Ridley, B A
EM: ridley@ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO 80307 United States
AU: Weinheimer, A J
EM: wein@ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO 80307 United States
AU: Knapp, D J
EM: knapp@ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO 80307 United States
AU: Montzka, D D
EM: montzka@ucar.edu
AF: Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO 80307 United States
AU: Baumgardner, D
EM: darrel@servidor.unam.mx
AF: Universidad Nacional Autonoma de Mexico, Centro de Cienceas de la Atmosfera, Ciudad Universitaria, Mexico DF, 04510 Mexico
AU: Garrett, T J
EM: tgarrett@met.utah.edu
AF: Department of Meteorology, University of Utah, Salt Lake City, UT 84112 United States
AU: Weinstock, E M
EM: weinstock@huarp.harvard.edu
AF: Atmospheric Research Project, Harvard University, Cambridge, MA 02138
AU: Smith, J B
EM: jsmith@huarp.harvard.edu
AF: Atmospheric Research Project, Harvard University, Cambridge, MA 02138
AU: Sayres, D S
EM: dsayres@huarp.harvard.edu
AF: Atmospheric Research Project, Harvard University, Cambridge, MA 02138
AU: Pittman, J V
EM: jvellovic@huarp.harvard.edu
AF: Atmospheric Research Project, Harvard University, Cambridge, MA 02138
AU: Dhaniyala, S
EM: sdhaniya@clarkson.edu
AF: Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY 13699 United States
AU: Bui, T P
EM: pbui@mail.arc.nasa.gov
AF: Ames Research Center, National Aeronautics and Space Administration, Moffett Field, CA 94035 United States
AU: Mahoney, M J
EM: Michael.J.Mahoney@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 United States
AB: The redistribution of HNO$_{3}$ via uptake and sedimentation by cirrus cloud particles is considered an important term in the upper tropospheric budget of reactive nitrogen. Numerous cirrus cloud encounters by the NASA WB-57F high-altitude research aircraft during CRYSTAL-FACE were accompanied by the observation of condensed-phase HNO$_{3}$ with the NOAA chemical ionization mass spectrometer. The instrument measures HNO$_{3}$ with two independent channels of detection connected to separate forward- and downward-facing inlets that allow a determination of the amount of HNO$_{3}$ condensed on ice particles. Subtropical cirrus clouds, as indicated by the presence of ice particles, were observed coincident with condensed-phase HNO$_{3}$ at temperatures of 197 K - 224 K and pressures of 120 hPa - 224 hPa. Maximum levels of condensed-phase HNO$_{3}$ approached the gas-phase equivalent of 0.8 ppbv. Ice particle surface coverages as high as 1.4x10 $^{14}$ molecules cm$^{-2}$ (14% of a HNO$_{3}$ monolayer) were observed. A dissociative Langmuir adsorption model, when using an empirically derived HNO$_{3}$ adsorption enthalpy of -11.0 kcal mol$^{-1}$, effectively describes the observed molecular coverages to within a factor of 5. The percentage of total HNO3 in the condensed phase ranged from near zero to 100% in the observed cirrus clouds. With volume-weighted mean particle diameters up to 700 microns and particle fall velocities up to 10 m s$^{-1}$, some observed clouds have significant potential to redistribute HNO$_{3}$ in the upper troposphere.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting