Journal Article

PreJuSER-13903

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Impact of deep convection in the tropical tropopause layer in West Africa: in-situ observations and mesoscale modelling

Fierli, F. ; Orlandi, E. ; Law, K. S. ; Cagnazzo, c. ; Borrmann, S. ; Cairo, F. ; Schiller, C.FZJ* ; Ravegnani, F. ; Volk, M.

2011
EGU Katlenburg-Lindau

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Please use a persistent id in citations: http://hdl.handle.net/2128/10028

Abstract: We present the analysis of the impact of convection on the composition of the tropical tropopause layer region (TTL) in West-Africa during the AMMA-SCOUT campaign. Geophysica M55 aircraft observations of water vapor, ozone, aerosol and CO2 during August 2006 show perturbed values at altitudes ranging from 14 km to 17 km (above the main convective outflow) and satellite data indicates that air detrainment is likely to have originated from convective cloud east of the flights. Simulations of the BOLAM mesoscale model, nudged with infrared radiance temperatures, are used to estimate the convective impact in the upper troposphere and to assess the fraction of air processed by convection. The analysis shows that BOLAM correctly reproduces the location and the vertical structure of convective outflow. Model-aided analysis indicates that convection can influence the composition of the upper troposphere above the level of main outflow for an event of deep convection close to the observation site. Model analysis also shows that deep convection occurring in the entire Sahelian transect (up to 2000 km E of the measurement area) has a non negligible role in determining TTL composition.

Keyword(s): J

Note: The authors acknowledge the partial support of the EC SCOUT-O3 Integrated Project (505390-GOCE-CT-2004). This work was partly supported by AMMA project. Based on French initiative, AMMA was built by an international scientific group and is currently funded by a large number of agencies, especially from France, UK, US and Africa. It has been the beneficiary of a major financial contribution from the European Community's Sixth Framework Research Programme. We acknowledge the anonymous reviewers for their valuable suggestions.

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Contributing Institute(s):

1. Stratosphäre (IEK-7)

Research Program(s):

1. Atmosphäre und Klima (P23)

Appears in the scientific report 2011

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