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Title: An Observational Study on Cloud Spectral Width in North China

Abstract

Cloud droplet size distribution (CDSD) is a critical characteristic for a number of processes related to clouds, considering that cloud droplets are formed in different sizes above the cloud-base. This paper analyzes the in-situ aircraft measurements of CDSDs and aerosol concentration ( N a ) performed in stratiform clouds in Hebei, China, in 2015 to reveal the characteristics of cloud spectral width, commonly known as relative dispersion ( ε , ratio of standard deviation (σ) to mean radius (r) of the CDSD). A new algorithm is developed to calculate the contributions of droplets of different sizes to ε . It is found that small droplets with the size range of 1 to 5.5 μm and medium droplets with the size range of 5.5 to 10 μm are the major contributors to ε, and the medium droplets generally dominate the change of ε. The variation of ε with N a can be well explained by comparing the normalized changes of σ and r ( k σ/σ and k r/r ), rather than k σ and k r only ( k σ is Δσ/Δ N a and k r is Δr/Δ N a ). From the perspective of external factors affecting εmore » change, the effects of N a and condensation are examined. As a result, it is found that ε increases initially and decreases afterward as N a increases, and “condensational broadening” occurs up to 1 km above cloud-base, potentially providing observational evidence for recent numerical simulations in the literature.« less

Authors:
ORCiD logo [1];  [1];  [1]; ORCiD logo [2];  [3];  [4]
  1. Nanjing Univ. of Information Science & Technology, Nanjing (China)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  4. Hebei Weather Modification Office, Shijiazhuang (China)
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1497378
Report Number(s):
BNL-211312-2019-JAAM
Journal ID: ISSN 2073-4433; ATMOCZ
Grant/Contract Number:  
SC0012704
Resource Type:
Accepted Manuscript
Journal Name:
Atmosphere (Basel)
Additional Journal Information:
Journal Name: Atmosphere (Basel); Journal Volume: 10; Journal Issue: 3; Journal ID: ISSN 2073-4433
Publisher:
MDPI
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; cloud droplet spectral dispersion; aerosol concentration; height above cloud-base; aircraft observations

Citation Formats

Wang, Yuan, Niu, Shengjie, Lu, Chunsong, Liu, Yangang, Chen, Jingyi, and Yang, Wenxia. An Observational Study on Cloud Spectral Width in North China. United States: N. p., 2019. Web. doi:10.3390/atmos10030109.
Wang, Yuan, Niu, Shengjie, Lu, Chunsong, Liu, Yangang, Chen, Jingyi, & Yang, Wenxia. An Observational Study on Cloud Spectral Width in North China. United States. doi:10.3390/atmos10030109.
Wang, Yuan, Niu, Shengjie, Lu, Chunsong, Liu, Yangang, Chen, Jingyi, and Yang, Wenxia. Fri . "An Observational Study on Cloud Spectral Width in North China". United States. doi:10.3390/atmos10030109. https://www.osti.gov/servlets/purl/1497378.
@article{osti_1497378,
title = {An Observational Study on Cloud Spectral Width in North China},
author = {Wang, Yuan and Niu, Shengjie and Lu, Chunsong and Liu, Yangang and Chen, Jingyi and Yang, Wenxia},
abstractNote = {Cloud droplet size distribution (CDSD) is a critical characteristic for a number of processes related to clouds, considering that cloud droplets are formed in different sizes above the cloud-base. This paper analyzes the in-situ aircraft measurements of CDSDs and aerosol concentration ( Na ) performed in stratiform clouds in Hebei, China, in 2015 to reveal the characteristics of cloud spectral width, commonly known as relative dispersion ( ε , ratio of standard deviation (σ) to mean radius (r) of the CDSD). A new algorithm is developed to calculate the contributions of droplets of different sizes to ε . It is found that small droplets with the size range of 1 to 5.5 μm and medium droplets with the size range of 5.5 to 10 μm are the major contributors to ε, and the medium droplets generally dominate the change of ε. The variation of ε with Na can be well explained by comparing the normalized changes of σ and r ( kσ/σ and kr/r ), rather than kσ and k r only ( kσ is Δσ/Δ Na and kr is Δr/Δ Na ). From the perspective of external factors affecting ε change, the effects of Na and condensation are examined. As a result, it is found that ε increases initially and decreases afterward as Na increases, and “condensational broadening” occurs up to 1 km above cloud-base, potentially providing observational evidence for recent numerical simulations in the literature.},
doi = {10.3390/atmos10030109},
journal = {Atmosphere (Basel)},
number = 3,
volume = 10,
place = {United States},
year = {2019},
month = {3}
}

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