Spectral width of cloud droplet spectra is crucial to the parameterization of cloud optical depth, assessment of indirect aerosol effect, and the formation of precipitation in numerical simulation. Based on aircraft observations of cloud microphysics in stratocumulus on 19 July 2008, during the Physics of Stratocumulus Top (POST) field campaign, the vertical distribution of microphysical properties and cloud droplet spectra were analyzed, as were the cloud microphysical processes. Results showed that spectral width of cloud droplet spectra was basically larger near the cloud base, which is due to aerosol nucleation. Spectral width decreased as height increased in the middle layer of the cloud, which was caused by condensational growth. The increase in spectral width near the cloud top was caused by entrainment-mixing processes. The increase in vertical velocity in the adiabatic cloud increased cloud droplet number concentration by promoting the activation of cloud condensation nuclei (CCN), increased cloud droplet size, and led to the decrease in spectral width by promoting condensational growth. This ultimately led to the negative correlation between spectral width and cloud droplet number concentration as well as cloud droplet size. The decrease in vertical velocity caused by entrainment-mixing processes in cloud holes decreased cloud droplet number concentration and cloud droplet size and increased spectral width by promoting the evaporation of cloud droplets. This was enhanced by the decrease in the adiabatic fraction. Based on these observations, it is recommended that the parameterization of the spectral width of cloud droplet spectra takes into account vertical velocity, cloud droplet number concentration, cloud droplet size, adiabatic fraction, etc.
|Translated title of the contribution||Spectral Width of Cloud Droplet Spectra and Its Impact Factors in Marine Stratocumulus|
|Original language||Chinese (Traditional)|
|Number of pages||16|
|Journal||Chinese Journal of Atmospheric Sciences|
|Publication status||Published - 2020 May 15|
Bibliographical noteFunding Information:
作者简介 朱磊，男，1995 年出生，硕士研究生，主要从事云降水物理方向研究。E-mail: firstname.lastname@example.org 通讯作者 陆春松，E-mail: email@example.com 资助项目 国家重点研发计划项目 2017YFA0604001，江苏省自然科学基金杰出青年基金项目 BK20160041，国家自然科学基金项目 41822504， 青蓝工程 R2018Q05，江苏省六大人才高峰 2015-JY-011 Funded by National Key Research and Development Program of China (Grant 2017YFA0604001), Natural Science Foundation of Jiangsu Province, China (Grant BK20160041), National Natural Science Foundation of China (Grant 41822504), Qinglan Project of Jiangsu Province, China (Grant R2018Q05), Six Talent Peak Project in Jiangsu, China (Grant 2015-JY-011)
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All Science Journal Classification (ASJC) codes
- Atmospheric Science