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Aerosol–Cloud Interaction at the Summit of Mt. Fuji, Japan: Factors Influencing Cloud Droplet Number Concentrations

Authors :
Yoko Iwamoto
Ayami Watanabe
Ryota Kataoka
Mitsuo Uematsu
Kazuhiko Miura
Source :
Applied Sciences, Vol 11, Iss 18, p 8439 (2021)
Publication Year :
2021
Publisher :
MDPI AG, 2021.

Abstract

To investigate interactions between aerosols and clouds, the size and number concentrations of the cloud condensation nuclei (CCN) and the cloud droplets (CDs) were measured at the summit of Mt. Fuji (altitude 3776 m), Japan. The CCN number concentrations (NCCN) are significantly higher in continental air masses than in air masses from the Pacific Ocean. The hygroscopicity parameter κ did not change much for different air mass origins, indicating that aerosol particles in the free troposphere are well mixed. Based on the CD number concentrations (NCD), the degree of supersaturation in the ambient air during the cloud-shrouded period was estimated to be 0.15% (25th percentile) to 0.44% (75th percentile). To evaluate factors influencing the NCD, measured NCD were compared to ones calculated based on the Köhler theory using aerosol number size distributions, κ, and the degree of supersaturation. The results showed that NCD could not be reproduced satisfyingly when the mean number size distribution or the mean effective supersaturation were used for the calculation. This study highlights the importance of obtaining information about the degree of supersaturation to predict NCD in the atmosphere.

Details

Language :
English
ISSN :
20763417
Volume :
11
Issue :
18
Database :
Directory of Open Access Journals
Journal :
Applied Sciences
Publication Type :
Academic Journal
Accession number :
edsdoj.2239a3d552344ceeb4f67a3d7d483c84
Document Type :
article
Full Text :
https://doi.org/10.3390/app11188439