HR: 17:30h
AN: A44C-07    [Abstracts]
TI: The observation of nitric acid-containing particles in the tropical lower stratosphere
AU: * Popp, P J
EM: peter.j.popp@noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305
AU: * Popp, P J
EM: peter.j.popp@noaa.gov
AF: CIRES, University of Colorado, Boulder, CO 80309
AU: Marcy, T P
EM: timothy.p.marcy@noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305
AU: Marcy, T P
EM: timothy.p.marcy@noaa.gov
AF: CIRES, University of Colorado, Boulder, CO 80309
AU: Jensen, E J
EM: ejensen@cirrus.arc.nasa.gov
AF: Ames Research Center, National Aeronautics and Space Administration, Moffett Field, CA 94035
AU: Kaercher, B
EM: bernd.kaercher@dlr.de
AF: Institut fur Physik der Atmosphare, DLR, Oberpfaffenhofen, D-82234 Germany
AU: Fahey, D W
EM: david.w.fahey@noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305
AU: Gao, R S
EM: gao@al.noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305
AU: Thompson, T L
EM: tlt@al.noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305
AU: Rosenlof, K H
EM: karen.h.rosenlof@noaa.gov
AF: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305
AU: Richard, E C
EM: erik.richard@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303
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: jxsmith@huarp.harvard.edu
AF: Atmospheric Research Project, Harvard University, Cambridge, MA 02138
AU: May, R D
EM: rmay@maycomm.com
AF: MayComm Instruments, MayComm Instruments, San Dimas, CA 91773
AU: Voemel, H
EM: holger.voemel@noaa.gov
AF: Climate Monitoring and Diagnostics Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305
AU: Wilson, J C
EM: jwilson@du.edu
AF: Department of Engineering, University of Denver, Denver, CO 80208
AU: Heymsfield, A J
EM: heyms1@ucar.edu
AF: Mesocscale and Microscale Meteorology Division, National Center for Atmospheric Research, Boulder, CO 80301
AU: Mahoney, M J
EM: michael.j.mahoney@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
AU: Thompson, A M
EM: anne@met.psu.edu
AF: Department of Meteorology, Pennsylvania State University, University Park, PA 16802
AB: Airborne in situ measurements over the eastern Pacific Ocean in January 2004 during the NASA Pre-Aura Validation Experiment have revealed a new category of nitric acid-containing particles in the tropical lower stratosphere. These particles are most likely composed of nitric acid trihydrate (NAT). They were observed in a narrow layer above the tropopause (18±0.1 km) and over a broad geographic extent (>1100 km). In contrast to the background liquid sulfate aerosol, these particles are solid, much larger (1.7-4.7 μm vs. 0.1 μm), and significantly less abundant (<10^-4 cm^-3 vs. 10 cm^-3). Microphysical trajectory models suggest that the NAT particles grow over a 6-14 day period in supersaturated air that remains close to the tropical tropopause and might be a common feature in the tropics. The small number density of these particles implies a highly selective or slow nucleation process. Understanding the formation of solid NAT particles in the tropics could improve our understanding of stratospheric nucleation processes in polar regions and, therefore, dehydration and denitrification.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005