HR: 0800h
AN: A21B-0746    [Abstracts]
TI: Observations of Gas- and Condensed-Phase Nitric Acid in the Tropical Upper Troposphere and Lower Stratosphere
AU: * Popp, P J
EM: peter.j.popp@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, R/AL6, Boulder, CO 80305
AU: * Popp, P J
EM: peter.j.popp@noaa.gov
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309
AU: Gao, R S
EM: gao@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, R/AL6, Boulder, CO 80305
AU: Marcy, T P
EM: tmarcy@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, R/AL6, Boulder, CO 80305
AU: Marcy, T P
EM: tmarcy@al.noaa.gov
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309
AU: Fahey, D W
EM: fahey@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, R/AL6, Boulder, CO 80305
AU: Fahey, D W
EM: fahey@al.noaa.gov
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309
AU: Thompson, T L
EM: tlt@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, R/AL6, Boulder, CO 80305
AU: Herman, R L
EM: robert.l.herman@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
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: Pittman, J V
EM: vellovic@huarp.harvard.edu
AF: Atmospheric Research Project, Harvard University, Cambridge, MA 02138
AU: Sayres, D S
EM: sayres@huarp.harvard.edu
AF: Atmospheric Research Project, Harvard University, Cambridge, MA 02138
AU: Wilson, J C
EM: jwilson@du.edu
AF: Department of Engineering, University of Denver, Denver, CO 80208
AU: Dhaniyala, S
AF: Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY 13699
AU: Mahoney, M J
EM: michael.j.mahoney@jpl.nasa.gov
AF: Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY 13699
AB: Nitric acid (HNO$_{3}$) serves as the primary reservoir species for nitrogen oxides, which are directly involved in the photochemical production of tropospheric ozone. Gas- and condensed-phase HNO$_{3}$ were observed for the first time in the tropical upper troposphere and lower stratosphere (UT/LS) during the NASA Pre-Aura Validation Experiment (Pre-AVE) in January, 2004, onboard the WB-57F high-altitude research aircraft. Vertical profiles of HNO$_{3}$ in the UT/LS reveal low values (150 pptv or less) near the tropical tropopause. Individual nitric acid-containing particles were observed between 3\deg S and 7\deg N during two Pre-AVE flights in the LS. These particles were observed at 18 km altitude and temperatures of 188-192 K, with number densities of 10$^{-4}$-10$^{-6}$ cm$^{-3}$. Understanding the formation mechanism of these particles might provide insight into ice particle formation at the tropical tropopause and the selective nucleation process for large nitric acid trihydrate (NAT) particles previously observed in the Arctic lower stratosphere.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting