Comprehensive quantification of height dependence of entrainment mixing between stratiform cloud top and environment
<p>Different entrainment-mixing processes of turbulence are crucial to processes related to clouds; however, only a few qualitative studies have been concentrated on the vertical distributions of entrainment-mixing mechanisms with low vertical resolutions. To quantitatively study vertical prof...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-07-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/21/11225/2021/acp-21-11225-2021.pdf |
| Summary: | <p>Different entrainment-mixing processes of turbulence are crucial to processes
related to clouds; however, only a few qualitative studies have been
concentrated on the vertical distributions of entrainment-mixing mechanisms
with low vertical resolutions. To quantitatively study vertical profiles of
entrainment-mixing mechanisms with a high resolution, the stratiform clouds
observed in the Physics of Stratocumulus Top (POST) project are examined. The
unique sawtooth flight pattern allows for an examination of the vertical
distributions of entrainment-mixing mechanisms with a 5 <span class="inline-formula">m</span> vertical
resolution. Relative standard deviation of volume mean radius divided by
relative standard deviation of liquid water content is introduced to be a new
estimation of microphysical homogeneous mixing degree, to overcome
difficulties of determining the adiabatic microphysical properties required in
existing measures. The vertical profile of this new measure indicates that
entrainment-mixing mechanisms become more homogeneous with decreasing
altitudes and are consistent with the dynamical measures of Damköhler number
and transition scale number. Further analysis shows that the vertical
variation of entrainment-mixing mechanisms with decreasing altitudes is due to
the increases of turbulent dissipation rate in cloud and relative humidity in
droplet-free air and the decrease of size of droplet-free air. The results
offer insights into the theoretical understanding and parameterizations of
vertical variation of entrainment-mixing mechanisms.</p> |
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| ISSN: | 1680-7316 1680-7324 |