Joint Seminar: The impact of land-sea contrasts on the aggregation of convection

The self-aggregation of convection in idealised models has been widely studied. Work has been done to identify key physical mechanisms responsible for both driving and maintaining aggregation in a range of idealised radiative-convective equilibrium (RCE) models. These idealised models are typically run without any land, rotation, variation in sea-surface temperatures (SSTs), or a diurnal cycle. Due to these idealisations, a key question in the study of convective aggregation is how these convective processes and mechanisms manifest in the real-world. Several studies have tried to tackle this question by increasing the complexity of processes in the idealised models, such as SST gradients, adding a slab ocean, adding a diurnal cycle, or adding an aerosol diabatic heating perturbation. Particularly, the inclusion of interactive ocean surfaces has been shown to strongly impact the formation of aggregated clusters.

We approach this question by adding an idealized flat, continentally-sized island into an RCE model to investigate how land-sea contrasts impact convective aggregation and its mechanisms. We show that convection preferentially forms over the island in our simulations, forced by a large-scale thermally driven circulation. This circulation is initially triggered by a land-sea thermal contrast, and is later maintained through longwave radiative feedbacks. Finally, we will compare the essential mechanisms for aggregation in these simulations, with aquaplanet aggregation simulations through mechanism denial tests.




13:30 h


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


Elisabeth Dingley


Cathy Hohenegger

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