HR: 11:05h
AN: A12A-04    [Abstracts]
TI: Measurements of HCl in the TTL
AU: * Marcy, T P
EM: Timothy.P.Marcy@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway R/AL6, Boulder, CO 80305
AU: Popp, P J
EM: ppopp@al/noaa/gov
AF: NOAA Aeronomy Laboratory, 325 Broadway R/AL6, Boulder, CO 80305
AU: Gao, R
EM: gao@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway R/AL6, Boulder, CO 80305
AU: Fahey, D W
EM: fahey@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway R/AL6, Boulder, CO 80305
AU: Richard, E
EM: erichard@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway R/AL6, Boulder, CO 80305
AU: Thompson, T
EM: tlt@al.noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway R/AL6, Boulder, CO 80305
AU: Lowenstein, M
EM: mloewenstein@mail.arc.nasa.gov
AF: NASA, Ames Research Center, Moffett Field, CA 94035
AU: Weinstock, E M
EM: weinstock@huarp.harvard.edu
AF: Harvard University, HUARP, Cambridge, MA 02138
AB: We have measured HCl and HNO$_{3}$ abundances in the tropical tropopause layer (TTL) by chemical ionization mass spectrometry (CIMS). The measurements were made from the NASA WB-57F high alitiude aircraft flying from Costa Rica over the eastern Pacific Ocean in January 2004. The observed HCl and HNO$_{3}$ increase sharply above the thermal tropopause, as expected. Average HCl values range from 10 to 50 ppt in the TTL and are near zero at lower altitudes. This, along with the presence of increased HNO3 below the TTL, suggests that the HCl in the TTL does not come from below, in the free troposphere. HCl in the TTL indicates either transport of stratospheric air into the TTL or possible in situ production of HCl from short-lived organic species. Concentrations of other tracers, such as H$_{2}$O and CO indicate that HCl containing air in the TTL also has substantial tropospheric character. These measurements constrain the HCl budget in the TTL and, with use of the correlations of HCl with the simultaneously measured ozone, provide an upper bound for the fraction of the ozone in the TTL that has also been transported from the stratosphere.
DE: 3362 Stratosphere/troposphere interactions
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting