title: Quantifying stratospheric ozone in the upper troposphere with in situ measurements of HCl.
abstract: We have developed a chemical ionization mass spectrometry technique for precise in situ measurements of hydrochloric acid (HCl) from a high-altitude aircraft. In measurements at subtropical latitudes, minimum HCl values found in the upper troposphere (UT) were often near or below the detection limit of the measurements (0.005 parts per billion by volume), indicating that background HCl values are much lower than a global mean estimate. However, significant abundances of HCl were observed in many UT air parcels, as a result of stratosphere-to-troposphere transport events. We developed a method for diagnosing the amount of stratospheric ozone in these UT parcels using the compact linear correlation of HCl with ozone found throughout the lower stratosphere (LS). Expanded use of this method will lead to improved quantification of cross-tropopause transport events and validation of global chemical transport models.
authors.affiliation: Aeronomy Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA. tmarcy@al.noaa.gov
authors.forename: T P
authors.initials: TP
authors.lastname: Marcy
authors.forename: D W
authors.initials: DW
authors.lastname: Fahey
authors.forename: R S
authors.initials: RS
authors.lastname: Gao
authors.forename: P J
authors.initials: PJ
authors.lastname: Popp
authors.forename: E C
authors.initials: EC
authors.lastname: Richard
authors.forename: T L
authors.initials: TL
authors.lastname: Thompson
authors.forename: K H
authors.initials: KH
authors.lastname: Rosenlof
authors.forename: E A
authors.initials: EA
authors.lastname: Ray
authors.forename: R J
authors.initials: RJ
authors.lastname: Salawitch
authors.forename: C S
authors.initials: CS
authors.lastname: Atherton
authors.forename: D J
authors.initials: DJ
authors.lastname: Bergmann
authors.forename: B A
authors.initials: BA
authors.lastname: Ridley
authors.forename: A J
authors.initials: AJ
authors.lastname: Weinheimer
authors.forename: M
authors.initials: M
authors.lastname: Loewenstein
authors.forename: E M
authors.initials: EM
authors.lastname: Weinstock
authors.forename: M J
authors.initials: MJ
authors.lastname: Mahoney