Joint Seminar: How does the very deep convection hydrate the stratosphere? Results from a Giga-LES of Hector the Convector

The very deep convection transports tropospheric air and water directly into the stratosphere. This transport may be underestimated by the general circulation models due to their coarse resolution, limiting our capability to predict the future climate. The efficiency of this transport is analysed for the thunderstorm Hector the Convector using a numerical simulation, run with a resolution of 100 m and more than 1 billion grid points. This so-called Giga Large-Eddy Simulation is the finest ever used for a case of very deep convection. It allows to represent the full Hector across scales, from its mesoscale organisation to its most energetic eddies. The 200-km large thunderstorm is organised at the surface by the convergence lines. The latter appear along sea breeze fronts and are intensified by cold pools. The 10-km wide updrafts that reach the stratosphere develop above these convergence lines and are characterized by a very weak dilution. The km-scale eddies in the overshoots produce the irreversible mixing with the stratospheric air and finally the hydration. Sensitivity numerical experiments to the horizontal grid spacing show that a resolution of the order of 100 m is necessary for a reliable estimate of the hydration.




13:30 Uhr


Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg


Thibaut Dauhut, Laboratoire d'Aérologie, Toulouse


Cathy Hohenegger

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