Aerosol Properties and Their Influences on Marine Boundary Layer Cloud Condensation Nuclei over the Southern Ocean
Five overcast marine stratocumulus cases during the Southern Ocean Clouds Radiation Aerosol Transport Experimental Study (SOCRATES) aircraft field campaign were selected to examine aerosol and cloud condensation nuclei (CCN) properties with cloud influence. The Aitken- and accumulation-mode aerosols...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-08-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/14/8/1246 |
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| author | Xingyu Zhang Xiquan Dong Baike Xi Xiaojian Zheng |
| author_facet | Xingyu Zhang Xiquan Dong Baike Xi Xiaojian Zheng |
| author_sort | Xingyu Zhang |
| collection | DOAJ |
| description | Five overcast marine stratocumulus cases during the Southern Ocean Clouds Radiation Aerosol Transport Experimental Study (SOCRATES) aircraft field campaign were selected to examine aerosol and cloud condensation nuclei (CCN) properties with cloud influence. The Aitken- and accumulation-mode aerosols contributed approximately 70% and 30% of the total aerosols, respectively. The aerosol properties before and after periods of drizzle were investigated using in situ measurements during one case. Sub-cloud drizzle processes impacted accumulation-mode aerosols and CCN distribution. There was a nearly linear increase in CCN number concentration (N<sub>CCN</sub>) with supersaturation (S) during the ‘before drizzle’ period, but this was not true for the ‘after drizzle’ period, particularly when S > 0.4%. Using the hygroscopicity parameter (κ) to quantitatively investigate the chemical cloud-processing mechanisms, we found that higher κ values (>0.4) represent cloud-processing aerosols, while lower κ values (<0.1) represent newly formed aerosols. When the supersaturation is less than the Hoppel minimum (0.22%), cloud processing is dominant, whereas sea-spray aerosols are dominant contributors to CCN activation when S exceeds 0.22% but is less than 0.32%, the effective supersaturation threshold. Sea salt is considered a non-cloud-processing aerosol and is large and hygroscopic enough to form cloud droplets. |
| first_indexed | 2024-03-11T00:08:08Z |
| format | Article |
| id | doaj.art-10e124eb797242b29ff71b1724a392fe |
| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-03-11T00:08:08Z |
| publishDate | 2023-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Atmosphere |
| spelling | doaj.art-10e124eb797242b29ff71b1724a392fe2023-11-19T00:12:34ZengMDPI AGAtmosphere2073-44332023-08-01148124610.3390/atmos14081246Aerosol Properties and Their Influences on Marine Boundary Layer Cloud Condensation Nuclei over the Southern OceanXingyu Zhang0Xiquan Dong1Baike Xi2Xiaojian Zheng3Department of Hydrology and Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721, USADepartment of Hydrology and Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721, USADepartment of Hydrology and Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721, USADepartment of Hydrology and Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721, USAFive overcast marine stratocumulus cases during the Southern Ocean Clouds Radiation Aerosol Transport Experimental Study (SOCRATES) aircraft field campaign were selected to examine aerosol and cloud condensation nuclei (CCN) properties with cloud influence. The Aitken- and accumulation-mode aerosols contributed approximately 70% and 30% of the total aerosols, respectively. The aerosol properties before and after periods of drizzle were investigated using in situ measurements during one case. Sub-cloud drizzle processes impacted accumulation-mode aerosols and CCN distribution. There was a nearly linear increase in CCN number concentration (N<sub>CCN</sub>) with supersaturation (S) during the ‘before drizzle’ period, but this was not true for the ‘after drizzle’ period, particularly when S > 0.4%. Using the hygroscopicity parameter (κ) to quantitatively investigate the chemical cloud-processing mechanisms, we found that higher κ values (>0.4) represent cloud-processing aerosols, while lower κ values (<0.1) represent newly formed aerosols. When the supersaturation is less than the Hoppel minimum (0.22%), cloud processing is dominant, whereas sea-spray aerosols are dominant contributors to CCN activation when S exceeds 0.22% but is less than 0.32%, the effective supersaturation threshold. Sea salt is considered a non-cloud-processing aerosol and is large and hygroscopic enough to form cloud droplets.https://www.mdpi.com/2073-4433/14/8/1246aerosol and CCN properties above and below cloud regimes over the Southern Oceanchemical and physical cloud-processing mechanisms |
| spellingShingle | Xingyu Zhang Xiquan Dong Baike Xi Xiaojian Zheng Aerosol Properties and Their Influences on Marine Boundary Layer Cloud Condensation Nuclei over the Southern Ocean Atmosphere aerosol and CCN properties above and below cloud regimes over the Southern Ocean chemical and physical cloud-processing mechanisms |
| title | Aerosol Properties and Their Influences on Marine Boundary Layer Cloud Condensation Nuclei over the Southern Ocean |
| title_full | Aerosol Properties and Their Influences on Marine Boundary Layer Cloud Condensation Nuclei over the Southern Ocean |
| title_fullStr | Aerosol Properties and Their Influences on Marine Boundary Layer Cloud Condensation Nuclei over the Southern Ocean |
| title_full_unstemmed | Aerosol Properties and Their Influences on Marine Boundary Layer Cloud Condensation Nuclei over the Southern Ocean |
| title_short | Aerosol Properties and Their Influences on Marine Boundary Layer Cloud Condensation Nuclei over the Southern Ocean |
| title_sort | aerosol properties and their influences on marine boundary layer cloud condensation nuclei over the southern ocean |
| topic | aerosol and CCN properties above and below cloud regimes over the Southern Ocean chemical and physical cloud-processing mechanisms |
| url | https://www.mdpi.com/2073-4433/14/8/1246 |
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