气候变化领域集成服务门户(CCPortal): Marine productivity and synoptic meteorology drive summer-time variability in Southern Ocean aerosols

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DOI	10.5194/acp-20-8047-2020
	Marine productivity and synoptic meteorology drive summer-time variability in Southern Ocean aerosols
	Alroe J.; Cravigan L.T.; Miljevic B.; Johnson G.R.; Selleck P.; Humphries R.S.; Keywood M.D.; Chambers S.D.; Williams A.G.; Ristovski Z.D.
发表日期	2020
ISSN	1680-7316
起始页码	8047
结束页码	8062
卷号	20 期号:13
英文摘要	Cloud-radiation interactions over the Southern Ocean are not well constrained in climate models, in part due to uncertainties in the sources, concentrations, and cloud-forming potential of aerosol in this region. To date, most studies in this region have reported measurements from fixed terrestrial stations or a limited set of instrumentation and often present findings as broad seasonal or latitudinal trends. Here, we present an extensive set of aerosol and meteorological observations obtained during an austral summer cruise across the full width of the Southern Ocean south of Australia. Three episodes of continental-influenced air masses were identified, including an apparent transition between the Ferrel atmospheric cell and the polar cell at approximately 64span classCombining double low line"inline-formula" S, and accompanied by the highest median cloud condensation nuclei (CCN) concentrations, at 252 cmspan classCombining double low line"inline-formula"-3. During the other two episodes, synoptic-scale weather patterns diverted air masses across distances greater than 1000 km from the Australian and Antarctic coastlines, respectively, indicating that a large proportion of the Southern Ocean may be periodically influenced by continental air masses. In all three cases, a highly cloud-active accumulation mode dominated the size distribution, with up to 93 % of the total number concentration activating as CCN. Frequent cyclonic weather conditions were observed at high latitudes and the associated strong wind speeds led to predictions of high concentrations of sea spray aerosol. However, these modelled concentrations were not achieved due to increased aerosol scavenging rates from precipitation and convective transport into the free troposphere, which decoupled the air mass from the sea spray flux at the ocean surface. CCN concentrations were more strongly impacted by high concentrations of large-diameter Aitken mode aerosol in air masses which passed over regions of elevated marine biological productivity, potentially contributing up to 56 % of the cloud condensation nuclei concentration. Weather systems were vital for aerosol growth in biologically influenced air masses and in their absence ultrafine aerosol diameters were less than 30 nm. These results demonstrate that air mass meteorological history must be considered when modelling sea spray concentrations and highlight the potential importance of sub-grid-scale variability when modelling atmospheric conditions in the remote Southern Ocean. © 2020 Copernicus GmbH. All rights reserved.
语种	英语
scopus关键词	aerosol; air mass; biological production; climate modeling; cloud condensation nucleus; marine environment; summer; synoptic meteorology; Australia; Southern Ocean
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/141225
作者单位	School of Earth and Atmospheric Sciences, Queensland University of Technology, Brisbane, Australia; Climate Science Centre, CSIRO Oceans and Atmosphere, Aspendale, Australia; Environmental Research, ANSTO, Lucas Heights, Australia
推荐引用方式 GB/T 7714	Alroe J.,Cravigan L.T.,Miljevic B.,et al. Marine productivity and synoptic meteorology drive summer-time variability in Southern Ocean aerosols[J],2020,20(13).
APA	Alroe J..,Cravigan L.T..,Miljevic B..,Johnson G.R..,Selleck P..,...&Ristovski Z.D..(2020).Marine productivity and synoptic meteorology drive summer-time variability in Southern Ocean aerosols.Atmospheric Chemistry and Physics,20(13).
MLA	Alroe J.,et al."Marine productivity and synoptic meteorology drive summer-time variability in Southern Ocean aerosols".Atmospheric Chemistry and Physics 20.13(2020).