Influences of an entrainment–mixing parameterization on numerical simulations of cumulus and stratocumulus clouds
<p>Different entrainment–mixing processes can occur in clouds; however, a homogeneous mixing mechanism is often implicitly assumed in most commonly used microphysics schemes. Here, we first present a new entrainment–mixing parameterization that uses the grid mean relative humidity without requ...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-04-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/5459/2022/acp-22-5459-2022.pdf |
| _version_ | 1828850375554236416 |
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| author | X. Xu X. Xu X. Xu C. Lu Y. Liu S. Luo S. Luo X. Zhou S. Endo L. Zhu Y. Wang |
| author_facet | X. Xu X. Xu X. Xu C. Lu Y. Liu S. Luo S. Luo X. Zhou S. Endo L. Zhu Y. Wang |
| author_sort | X. Xu |
| collection | DOAJ |
| description | <p>Different entrainment–mixing processes can occur in clouds; however, a homogeneous mixing mechanism is often implicitly assumed in most commonly used microphysics schemes. Here, we first present a new entrainment–mixing parameterization that uses the grid mean relative humidity without requiring
the relative humidity of the entrained air. Then, the parameterization is
implemented in a microphysics scheme in a large eddy simulation model, and
sensitivity experiments are conducted to compare the new parameterization
with the default homogeneous entrainment–mixing parameterization. The
results indicate that the new entrainment–mixing parameterization has a
larger impact on the number concentration, volume mean radius, and cloud
optical depth in the stratocumulus case than in the cumulus case. This is
because inhomogeneous and homogeneous mixing mechanisms dominate in the
stratocumulus and cumulus cases, respectively, which is mainly due to the
larger turbulence dissipation rate in the cumulus case. Because
stratocumulus clouds break up during the dissipation stage to form cumulus
clouds, the effects of this new entrainment–mixing parameterization during
the stratocumulus dissipation stage are between those during the
stratocumulus mature stage and the cumulus case. A large aerosol
concentration can enhance the effects of this new entrainment–mixing
parameterization by decreasing the cloud droplet size and evaporation timescale. The results of this new entrainment–mixing parameterization with
grid mean relative humidity are validated by the use of a different
entrainment–mixing parameterization that uses parameterized entrained air
properties. This study sheds new light on the improvement of
entrainment–mixing parameterizations in models.</p> |
| first_indexed | 2024-12-12T23:10:45Z |
| format | Article |
| id | doaj.art-e8280d4d44194b77bd6cdce67d3b710e |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-12T23:10:45Z |
| publishDate | 2022-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-e8280d4d44194b77bd6cdce67d3b710e2022-12-22T00:08:36ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242022-04-01225459547510.5194/acp-22-5459-2022Influences of an entrainment–mixing parameterization on numerical simulations of cumulus and stratocumulus cloudsX. Xu0X. Xu1X. Xu2C. Lu3Y. Liu4S. Luo5S. Luo6X. Zhou7S. Endo8L. Zhu9Y. Wang10Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing, ChinaNanjing Joint Institute for Atmospheric Sciences, Nanjing, ChinaKey Laboratory of Transportation Meteorology, CMA, Nanjing, ChinaKey Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing, ChinaEnvironmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, USAKey Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing, ChinaCollege of Aviation Meteorology, Civil Aviation Flight University of China, Guanghan, ChinaEnvironmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, USAEnvironmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, USAKey Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing, ChinaKey Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing, China<p>Different entrainment–mixing processes can occur in clouds; however, a homogeneous mixing mechanism is often implicitly assumed in most commonly used microphysics schemes. Here, we first present a new entrainment–mixing parameterization that uses the grid mean relative humidity without requiring the relative humidity of the entrained air. Then, the parameterization is implemented in a microphysics scheme in a large eddy simulation model, and sensitivity experiments are conducted to compare the new parameterization with the default homogeneous entrainment–mixing parameterization. The results indicate that the new entrainment–mixing parameterization has a larger impact on the number concentration, volume mean radius, and cloud optical depth in the stratocumulus case than in the cumulus case. This is because inhomogeneous and homogeneous mixing mechanisms dominate in the stratocumulus and cumulus cases, respectively, which is mainly due to the larger turbulence dissipation rate in the cumulus case. Because stratocumulus clouds break up during the dissipation stage to form cumulus clouds, the effects of this new entrainment–mixing parameterization during the stratocumulus dissipation stage are between those during the stratocumulus mature stage and the cumulus case. A large aerosol concentration can enhance the effects of this new entrainment–mixing parameterization by decreasing the cloud droplet size and evaporation timescale. The results of this new entrainment–mixing parameterization with grid mean relative humidity are validated by the use of a different entrainment–mixing parameterization that uses parameterized entrained air properties. This study sheds new light on the improvement of entrainment–mixing parameterizations in models.</p>https://acp.copernicus.org/articles/22/5459/2022/acp-22-5459-2022.pdf |
| spellingShingle | X. Xu X. Xu X. Xu C. Lu Y. Liu S. Luo S. Luo X. Zhou S. Endo L. Zhu Y. Wang Influences of an entrainment–mixing parameterization on numerical simulations of cumulus and stratocumulus clouds Atmospheric Chemistry and Physics |
| title | Influences of an entrainment–mixing parameterization on numerical simulations of cumulus and stratocumulus clouds |
| title_full | Influences of an entrainment–mixing parameterization on numerical simulations of cumulus and stratocumulus clouds |
| title_fullStr | Influences of an entrainment–mixing parameterization on numerical simulations of cumulus and stratocumulus clouds |
| title_full_unstemmed | Influences of an entrainment–mixing parameterization on numerical simulations of cumulus and stratocumulus clouds |
| title_short | Influences of an entrainment–mixing parameterization on numerical simulations of cumulus and stratocumulus clouds |
| title_sort | influences of an entrainment mixing parameterization on numerical simulations of cumulus and stratocumulus clouds |
| url | https://acp.copernicus.org/articles/22/5459/2022/acp-22-5459-2022.pdf |
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