Application of a new scheme of cloud base droplet nucleation in a spectral (bin) microphysics cloud model: sensitivity to aerosol size distribution
A new scheme of droplet nucleation at cloud base is implemented into the Hebrew University Cloud Model (HUCM) with spectral (bin) microphysics. In this scheme, supersaturation maximum <i>S</i><sub><mo>max</mo></sub> near cloud base is calculated using theoreti...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-11-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/14317/2016/acp-16-14317-2016.pdf |
| _version_ | 1818949556848558080 |
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| author | E. Ilotoviz A. Khain |
| author_facet | E. Ilotoviz A. Khain |
| author_sort | E. Ilotoviz |
| collection | DOAJ |
| description | A
new scheme of droplet nucleation at cloud base is implemented into the
Hebrew University Cloud Model (HUCM) with spectral (bin) microphysics. In
this scheme, supersaturation maximum <i>S</i><sub><mo>max</mo></sub> near cloud base is
calculated using theoretical results according to which <i>S</i><sub><mo>max</mo></sub> ∼ <i>w</i><sup>3∕4</sup><i>N</i><sub>d</sub><sup>−1∕2</sup>, where <i>w</i> is the vertical velocity at cloud base and
<i>N</i><sub>d</sub> is droplet concentration. Microphysical cloud structure obtained in
the simulations of a midlatitude hail storm using the new scheme is
compared with that obtained in the standard approach, in which droplet
nucleation is calculated using supersaturation calculated in grid points.
The simulations were performed with different concentrations of cloud
condensational nuclei (CCN) and with different shapes of CCN size spectra.
It is shown that the new nucleation scheme substantially improves the
vertical profile of droplet concentration shifting the concentration maximum
to cloud base. It is shown that the effect of the CCN size distribution
shape on cloud microphysics is not less important than the effect of the
total CCN concentration. It is shown that the smallest CCN with diameters
less than about 0.015 µm have a substantial effect on mixed-phase and
ice microphysics of deep convective clouds. Such CCN are not measured by
standard CCN probes, which hinders understanding of cold microphysical
processes. |
| first_indexed | 2024-12-20T09:04:35Z |
| format | Article |
| id | doaj.art-a6f5bc6c6a3d4431a2ff395f9d9bcb64 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-20T09:04:35Z |
| publishDate | 2016-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-a6f5bc6c6a3d4431a2ff395f9d9bcb642022-12-21T19:45:46ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242016-11-0116143171432910.5194/acp-16-14317-2016Application of a new scheme of cloud base droplet nucleation in a spectral (bin) microphysics cloud model: sensitivity to aerosol size distributionE. Ilotoviz0A. Khain1Department of Atmospheric Sciences, The Hebrew University of Jerusalem, Jerusalem, IsraelDepartment of Atmospheric Sciences, The Hebrew University of Jerusalem, Jerusalem, IsraelA new scheme of droplet nucleation at cloud base is implemented into the Hebrew University Cloud Model (HUCM) with spectral (bin) microphysics. In this scheme, supersaturation maximum <i>S</i><sub><mo>max</mo></sub> near cloud base is calculated using theoretical results according to which <i>S</i><sub><mo>max</mo></sub> ∼ <i>w</i><sup>3∕4</sup><i>N</i><sub>d</sub><sup>−1∕2</sup>, where <i>w</i> is the vertical velocity at cloud base and <i>N</i><sub>d</sub> is droplet concentration. Microphysical cloud structure obtained in the simulations of a midlatitude hail storm using the new scheme is compared with that obtained in the standard approach, in which droplet nucleation is calculated using supersaturation calculated in grid points. The simulations were performed with different concentrations of cloud condensational nuclei (CCN) and with different shapes of CCN size spectra. It is shown that the new nucleation scheme substantially improves the vertical profile of droplet concentration shifting the concentration maximum to cloud base. It is shown that the effect of the CCN size distribution shape on cloud microphysics is not less important than the effect of the total CCN concentration. It is shown that the smallest CCN with diameters less than about 0.015 µm have a substantial effect on mixed-phase and ice microphysics of deep convective clouds. Such CCN are not measured by standard CCN probes, which hinders understanding of cold microphysical processes.https://www.atmos-chem-phys.net/16/14317/2016/acp-16-14317-2016.pdf |
| spellingShingle | E. Ilotoviz A. Khain Application of a new scheme of cloud base droplet nucleation in a spectral (bin) microphysics cloud model: sensitivity to aerosol size distribution Atmospheric Chemistry and Physics |
| title | Application of a new scheme of cloud base droplet nucleation in a spectral (bin) microphysics cloud model: sensitivity to aerosol size distribution |
| title_full | Application of a new scheme of cloud base droplet nucleation in a spectral (bin) microphysics cloud model: sensitivity to aerosol size distribution |
| title_fullStr | Application of a new scheme of cloud base droplet nucleation in a spectral (bin) microphysics cloud model: sensitivity to aerosol size distribution |
| title_full_unstemmed | Application of a new scheme of cloud base droplet nucleation in a spectral (bin) microphysics cloud model: sensitivity to aerosol size distribution |
| title_short | Application of a new scheme of cloud base droplet nucleation in a spectral (bin) microphysics cloud model: sensitivity to aerosol size distribution |
| title_sort | application of a new scheme of cloud base droplet nucleation in a spectral bin microphysics cloud model sensitivity to aerosol size distribution |
| url | https://www.atmos-chem-phys.net/16/14317/2016/acp-16-14317-2016.pdf |
| work_keys_str_mv | AT eilotoviz applicationofanewschemeofcloudbasedropletnucleationinaspectralbinmicrophysicscloudmodelsensitivitytoaerosolsizedistribution AT akhain applicationofanewschemeofcloudbasedropletnucleationinaspectralbinmicrophysicscloudmodelsensitivitytoaerosolsizedistribution |