HR: 0800h
AN: A21B-0739    [Abstracts]
TI: Seasonal Variability of H$_{2}$O and O$_{3}$ in the UT/LS and Extent of the Extra-tropical Mixing Layer Based on Airborne SPURT Measurements
AU: * Krebsbach, M
EM: m.krebsbach@fz-juelich.de
AF: Research Centre Juelich GmbH, Institute for Chemistry and Dynamics of the Geosphere I: Stratosphere, Juelich, 52428 Germany
AU: Guenther, G
EM: g.guenther@fz-juelich.de
AF: Research Centre Juelich GmbH, Institute for Chemistry and Dynamics of the Geosphere I: Stratosphere, Juelich, 52428 Germany
AU: Spelten, N
EM: n.spelten@fz-juelich.de
AF: Research Centre Juelich GmbH, Institute for Chemistry and Dynamics of the Geosphere I: Stratosphere, Juelich, 52428 Germany
AU: Schiller, C
EM: c.schiller@fz-juelich.de
AF: Research Centre Juelich GmbH, Institute for Chemistry and Dynamics of the Geosphere I: Stratosphere, Juelich, 52428 Germany
AB: The data set presented in this study was obtained during the airborne project SPURT (german: trace gas transport in the tropopause region). The high-resolution \emph{in situ} measurements of a large set of trace gases, thereunder total water (H$_{2}$O) and ozone (O$_{3}$), took place over Europe between November $2001$ and July $2003$. Each annual season was investigated within $2$ campaigns in the region around the polar jet covering a broad latitude range between $20-80$^\circ$N. Based upon this data set, we derived a seasonal climatology and characteristics of trace gas distributions, their gradients and variability in that region. Significantly enhanced H$_{2}$O mixing ratios of several $10$\ ppmv near the tropopause and even higher up in the LS have been detected during all seasons. To get a comprehensive insight into processes, ranging and variability of the measured parameters in the investigated area, correlations, distributions as well as probability density distributions (PD) of the \emph{in situ} measured trace gases H$_{2}$O and O$_{3}$ were determined by using chemical, thermal and dynamical coordinates (e.g.\ potential temperature, potential vorticity, distance to the local tropopause, distance to the jet stream maximum wind speeds, equivalent latitude). The PDs serve as a tool to transform localised aircraft data to a more comprehensive view of the tropopause region. It appears that both trace gases show most compact distributions and are best correlated in the view of potential vorticity and distance to the local tropopause. The seasonal cycles of H$_{2}$O and O$_{3}$ in the UT and LS are also evident in the PDs. An extra-tropical mixing layer following the shape of the tropopause and/or surfaces of potential vorticity was identified. Based on Lagrangian studies this layer is supposed to be influenced by transport processes on time scales of days to weeks. From tracer-tracer-correlations the extent of this layer could be estimated to range from the local tropopause to approximately $8-9$\ PVU, independent from season. By long-term simulations using the J\"{u}lich CLaMS (Chemical Lagrangian Model of the Stratosphere) the tropospheric influence with enhanced H$_{2}$O values even beyond this layer could be reproduced which originates from transport on longer time scales.
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
DE: 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707)
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting