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 ε change, the effects of N_a and condensation are examined.more » 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:

Wang, Yuan  ^[1];

• Search DOE PAGES for author "Wang, Yuan"
• Search DOE PAGES for ORCID "0000-0002-8478-0096"

Niu, Shengjie ^[1]; Lu, Chunsong ^[1]; Liu, Yangang  ^[2];

• Search DOE PAGES for author "Liu, Yangang"
• Search DOE PAGES for ORCID "0000-0003-0238-0468"

Chen, Jingyi ^[3]; Yang, Wenxia ^[4]

---

+ Show Author Affiliations

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:

Fri Mar 01 00:00:00 EST 2019

Research Org.:

Brookhaven National Lab. (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

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