Abstract
This study investigated the impact of several cloud microphysical schemes on the trade wind cumulus in the large eddy simulation model. To highlight the differences due to the cloud microphysical component, we developed a fully compressible large eddy simulation model, which excluded the implicit scheme and approximations as much as possible. The three microphysical schemes, the one-moment bulk, two-moment bulk, and spectral bin schemes were used for sensitivity experiments in which the other components were fixed. Our new large eddy simulation model using a spectral bin scheme successfully reproduced trade wind cumuli, and reliable model performance was confirmed. Results of the sensitivity experiments indicated that precipitation simulated by the one-moment bulk scheme started earlier, and its total amount was larger than that of the other models. By contrast, precipitation simulated by the two-moment scheme started late, and its total amount was small. These results support those of a previous study. The analyses revealed that the expression of two processes, (1) the generation of cloud particles and (2) the conversion from small droplets to raindrops, were crucial to the results. The fast conversion from cloud to rain and the large amount of newly generated cloud particles at the cloud base led to evaporative cooling and subsequent stabilization in the sub-cloud layer. The latent heat released at higher layers by the condensation of cloud particles resulted in the development of the boundary layer top height.
| Original language | English |
|---|---|
| Article number | 23 |
| Journal | Progress in Earth and Planetary Science |
| Volume | 2 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2015 Dec 1 |
| Externally published | Yes |
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Keywords
- Large eddy simulation
- Shallow clouds
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
Cite this
Impacts of cloud microphysics on trade wind cumulus : which cloud microphysics processes contribute to the diversity in a large eddy simulation? / Sato, Yousuke; Nishizawa, Seiya; Yashiro, Hisashi; Miyamoto, Yoshiaki; Kajikawa, Yoshiyuki; Tomita, Hirofumi.
In: Progress in Earth and Planetary Science, Vol. 2, No. 1, 23, 01.12.2015.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Impacts of cloud microphysics on trade wind cumulus
T2 - which cloud microphysics processes contribute to the diversity in a large eddy simulation?
AU - Sato, Yousuke
AU - Nishizawa, Seiya
AU - Yashiro, Hisashi
AU - Miyamoto, Yoshiaki
AU - Kajikawa, Yoshiyuki
AU - Tomita, Hirofumi
PY - 2015/12/1
Y1 - 2015/12/1
N2 - This study investigated the impact of several cloud microphysical schemes on the trade wind cumulus in the large eddy simulation model. To highlight the differences due to the cloud microphysical component, we developed a fully compressible large eddy simulation model, which excluded the implicit scheme and approximations as much as possible. The three microphysical schemes, the one-moment bulk, two-moment bulk, and spectral bin schemes were used for sensitivity experiments in which the other components were fixed. Our new large eddy simulation model using a spectral bin scheme successfully reproduced trade wind cumuli, and reliable model performance was confirmed. Results of the sensitivity experiments indicated that precipitation simulated by the one-moment bulk scheme started earlier, and its total amount was larger than that of the other models. By contrast, precipitation simulated by the two-moment scheme started late, and its total amount was small. These results support those of a previous study. The analyses revealed that the expression of two processes, (1) the generation of cloud particles and (2) the conversion from small droplets to raindrops, were crucial to the results. The fast conversion from cloud to rain and the large amount of newly generated cloud particles at the cloud base led to evaporative cooling and subsequent stabilization in the sub-cloud layer. The latent heat released at higher layers by the condensation of cloud particles resulted in the development of the boundary layer top height.
AB - This study investigated the impact of several cloud microphysical schemes on the trade wind cumulus in the large eddy simulation model. To highlight the differences due to the cloud microphysical component, we developed a fully compressible large eddy simulation model, which excluded the implicit scheme and approximations as much as possible. The three microphysical schemes, the one-moment bulk, two-moment bulk, and spectral bin schemes were used for sensitivity experiments in which the other components were fixed. Our new large eddy simulation model using a spectral bin scheme successfully reproduced trade wind cumuli, and reliable model performance was confirmed. Results of the sensitivity experiments indicated that precipitation simulated by the one-moment bulk scheme started earlier, and its total amount was larger than that of the other models. By contrast, precipitation simulated by the two-moment scheme started late, and its total amount was small. These results support those of a previous study. The analyses revealed that the expression of two processes, (1) the generation of cloud particles and (2) the conversion from small droplets to raindrops, were crucial to the results. The fast conversion from cloud to rain and the large amount of newly generated cloud particles at the cloud base led to evaporative cooling and subsequent stabilization in the sub-cloud layer. The latent heat released at higher layers by the condensation of cloud particles resulted in the development of the boundary layer top height.
KW - Large eddy simulation
KW - Shallow clouds
UR - http://www.scopus.com/inward/record.url?scp=85040241611&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85040241611&partnerID=8YFLogxK
U2 - 10.1186/s40645-015-0053-6
DO - 10.1186/s40645-015-0053-6
M3 - Article
VL - 2
JO - Progress in Earth and Planetary Science
JF - Progress in Earth and Planetary Science
SN - 2197-4284
IS - 1
M1 - 23
ER -