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| Titel |
What determines the distribution of shallow convective mass flux through cloud base? |
| VerfasserIn |
Mirjana Sakradzija, Cathy Hohenegger |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250145999
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| Publikation (Nr.) |
 EGU/EGU2017-9985.pdf |
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| Zusammenfassung |
| The distribution of cumulus cloud population is studied using large-eddy simulations of two
shallow cumulus cases, one representing conditions over the tropical ocean, and another
representing mid-latitude conditions over land. In particular, the distribution of mass flux
through cloud base differs among these two cases on a log-log plot. The case over the ocean
shows a concave shape, while the case over land shows a straight line shape. The question of
this study is what sets these differences. We find that the magnitude of the surface fluxes and
its variation over the diurnal cycle do not influence the distribution shape. The latter is also
not controlled by the level of organization in the cloud filed. It is instead controlled by the
ratio of the surface sensible heat flux to the surface latent heat flux, the Bowen
ratio B. Using a theoretical thermodynamic cycle, we explain why B controls the
distribution shape and how it connects to the average mass flux per cloud ⟨m⟩. |
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