Joint Seminar: The vertical structure of the tropical atmosphere

The climatology of precipitation in the tropics is largely controlled by the distribution of large-scale ascent. Such ascending motion is often characterised as being either "top-heavy", with vertical motion peaking in the upper troposphere, or "bottom-heavy" with vertical motion peaking in the lower troposphere. This vertical structure plays a key role in determining precipitation rates and energy transports within the tropics, but the physical factors that control it remain uncertain.

In this talk, I will present a prototype theory for the vertical structure of the tropical overturning circulation based on a simple model of moist convection coupled to gravity wave dynamics. The theory elucidates how mixing and microphysical processes in moist convection influence the large-scale circulation, and it highlights the importance of small deviations in the lapse rate from that of a moist adiabat for determining its vertical structure. I will present observational support for some aspects of the simple model, but I will also explore its limitations. A full theory for the circulation's vertical structure requires incorporating radiative as well as dynamical constraints on the circulation, and including the effects of Bowen ratio variations over the land.




13:30 h


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


Jiawei Bao

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