Turbulence effects on warm-rain formation in precipitating shallow convection revisited
Two different collection kernels which include turbulence effects on the collision rate of liquid droplets are used as a basis to develop a parameterization of the warm-rain processes autoconversion, accretion, and self-collection. The new parameterization is tested and validated with the help o...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/12127/2016/acp-16-12127-2016.pdf |
| Summary: | Two different collection kernels which include turbulence effects on the
collision rate of liquid droplets are used as a basis to develop a
parameterization of the warm-rain processes autoconversion, accretion, and
self-collection. The new parameterization is tested and validated with the help
of a 1-D bin microphysics model. Large-eddy simulations of the rain formation
in shallow cumulus clouds confirm previous results that turbulence effects
can significantly enhance the development of rainwater in clouds and the
occurrence and amount of surface precipitation. The detailed behavior differs
significantly for the two turbulence models, revealing a considerable
uncertainty in our understanding of such effects. In addition, the
large-eddy simulations show a pronounced sensitivity to grid resolution, which
suggests that besides the effect of sub-grid small-scale isotropic
turbulence which is parameterized as part of the collection kernel also the
larger turbulent eddies play an important role for the formation of rain in
shallow clouds. |
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| ISSN: | 1680-7316 1680-7324 |