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| Titel |
Organization of tropical convection in low vertical wind shears: impact of boundary conditions |
| VerfasserIn |
Addisu Gezahegn Semie, Adrian Mark Tompkins |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250128476
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| Publikation (Nr.) |
 EGU/EGU2016-8465.pdf |
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| Zusammenfassung |
| Spontaneous organisation of convection is investigated using a cloud resolving model with a convection permitting horizontal resolution of 2 km. Convection spontaneously organises into clusters occurring in a single moist region surrounded by a dry convection-free region, reproducing the results of previous studies using a range of different models. Energy budget diagnostics are used to confirm the diabatic processes that lead to, or oppose, organisation as the simulations progress. A range of sensitivity experiments are then conducted to document the strength of the organisation to the representation of the sub-grid mixing, which confirm how the entrainment mixing into updraughts is key to the strength of the organised state. Schemes that produce low entrainment in the lower free-troposphere can destroy the organised state. Experiments are then conducted using a slab ocean lower boundary. Convection is still organised when using an interactive lower surface, as expected, but the degree of convective clustering in the moist region and the large-scale water vapour structures are altered, with sharper gradients and stronger bimodality. The mechanisms for this will be discussed. |
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