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Contribution of mixing to upward transport across the tropical tropopause layer (TTL)

Konopka, P. and Günther, G. and Müller, R. and dos Santos, F.H.S. and Schiller, C. and Ravegnani, F. and Ulanovsky, A. and Schlager, H. and Volk, C.M. and Viciani, S. and Pan, L.L. and McKenna, D.-S. (2007) Contribution of mixing to upward transport across the tropical tropopause layer (TTL). Atmospheric Chemistry and Physics, 7, pp. 3285-3308.

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Official URL: http://www.atmos-chem-phys.net/7/3285/2007/

Abstract

During the second part of the TROCCINOX campaign that took place in Brazil in early 2005, chemical species were measured on-board the high-altitude research aircraft Geophysica (ozone, water vapor, NO, NOy, CH<sub>4</sub> and CO) in the altitude range up to 20 km (or up to 450 K potential temperature), i.e. spanning the entire TTL region roughly extending between 350 and 420 K. Here, analysis of transport across the TTL is performed using a new version of the Chemical Lagrangian Model of the Stratosphere (CLaMS). In this new version, the stratospheric model has been extended to the earth surface. Above the tropopause, the isentropic and cross-isentropic advection in CLaMS is driven by meteorological analysis winds and heating/cooling rates derived from a radiation calculation. Below the tropopause, the model smoothly transforms from the isentropic to the hybrid-pressure coordinate and, in this way, takes into account the effect of large-scale convective transport as implemented in the vertical wind of the meteorological analysis. As in previous CLaMS simulations, the irreversible transport, i.e. mixing, is controlled by the local horizontal strain and vertical shear rates. Stratospheric and tropospheric signatures in the TTL can be seen both in the observations and in the model. The composition of air above ≈350 K is mainly controlled by mixing on a time scale of weeks or even months. Based on CLaMS transport studies where mixing can be completely switched off, we deduce that vertical mixing, mainly driven by the vertical shear in the tropical flanks of the subtropical jets and, to some extent, in the the outflow regions of the large-scale convection, offers an explanation for the upward transport of trace species from the main convective outflow at around 350 K up to the tropical tropopause around 380 K.

Document Type:Article
Title:Contribution of mixing to upward transport across the tropical tropopause layer (TTL)
Authors:
AuthorsInstitution or Email of Authors
Konopka, P.FZ Jülich, Jülich
Günther, G.FZ Jülich, Jülich
Müller, R.FZ Jülich, Jülich
dos Santos, F.H.S.FZ Jülich, Jülich
Schiller, C.FZ Jülich, Jülich
Ravegnani, F.CNR-ISAC, Bologna, I
Ulanovsky, A.CAO, Dolgoprudny, R
Schlager, H.UNSPECIFIED
Volk, C.M.Univ. Frankfurt,
Viciani, S.INOA, Firenze, I
Pan, L.L.NCAR, Boulder, CO, USA
McKenna, D.-S.NCAR, Boulder, CO, USA
Date:26 June 2007
Journal or Publication Title:Atmospheric Chemistry and Physics
Volume:7
Page Range:pp. 3285-3308
Status:Published
Keywords:Tropical tropopause layer, troposphere - stratosphere exchange, vertical transport
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EO - Erdbeobachtung
DLR - Research area:Space
DLR - Program:W EO - Erdbeobachtung
DLR - Research theme (Project):W - Vorhaben Atmosphären- und Klimaforschung (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Atmospheric Trace Species
Deposited By: Helga Jesse
Deposited On:17 Jul 2007
Last Modified:12 Dec 2013 20:26

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