TY  - JOUR
A1  - Palazzi, Elisa
A1  - Fierli, Federico
A1  - Cairo, Francesco
A1  - Cagnazzo, Chiara
A1  - Di Donfrancesco, Guido
A1  - Manzini, Elisa
A1  - Ravegnani, Fabrizio
A1  - Schiller, Cornelius
A1  - D'Amato, Francesco
A1  - Volk, C.-Michael
T1  - Diagnostics of the tropical tropopause layer from in-situ observations and CCM data
T2  - Atmospheric chemistry and physics / Discussions, 9.2009, S. 11659-11698
N2  - A suite of diagnostics is applied to in-situ aircraft measurements and one Chemistry-Climate Model (CCM) data to characterize the vertical structure of the Tropical Tropopause Layer (TTL). The diagnostics are based on the vertical tracers profiles, relative vertical tracers gradients, and tracer-tracer relationships in the tropical Upper Troposphere/Lower Stratosphere (UT/LS), using tropopause coordinates.
Observations come from the four tropical campaigns performed from 1998 to 2006 with the research aircraft Geophysica and have been directly compared to the output of the ECHAM5/MESSy CCM. The model vertical resolution in the TTL allows for appropriate comparison with high-resolution aircraft observations and the diagnostics used highlight common TTL features between the model and the observational data.
The analysis of the vertical profiles of water vapour, ozone, and nitrous oxide, in both the observations and the model, shows that concentration mixing ratios exhibit a strong gradient change across the tropical tropopause, due to the role of this latter as a transport barrier and that transition between the tropospheric and stratospheric regimes occurs within a finite layer. The use of relative vertical ozone gradients, in addition to the vertical profiles, helps to highlight the region where this transition occurs and allows to give an estimate of its thickness. The analysis of the CO-O3 and H2O-O3 scatter plots and of the Probability Distribution Function (PDF) of the H2O-O3 pair completes this picture as it allows to better distinguish tropospheric and stratospheric regimes that can be identified, first, by their differing chemical composition. 
The joint analysis and comparison of observed and modelled data allows us to evaluate the capability of the model in reproducing the observed vertical structure of the TTL and its variability, and also to assess whether observations from particular regions on a monthly timescale can be representative of the fine scale mean structure of the Tropical Tropopause Layer.
Y1  - 2009
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/26748
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-267487
UR  - www.atmos-chem-phys-discuss.net/9/11659/2009/
SN  - 1680-7375
SN  - 1680-7367
N1  - © Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License.
VL  - 9
SP  - 11659
EP  - 11698
PB  - European Geosciences Union
CY  - Katlenburg-Lindau
ER  -