气候变化领域集成服务门户(CCPortal): Impact of the variability in vertical separation between biomass burning aerosols and marine stratocumulus on cloud microphysical properties over the Southeast Atlantic

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DOI	10.5194/acp-21-4615-2021
	Impact of the variability in vertical separation between biomass burning aerosols and marine stratocumulus on cloud microphysical properties over the Southeast Atlantic
	Gupta S.; McFarquhar G.M.; O'Brien J.R.; Delene D.J.; Poellot M.R.; Dobracki A.; Podolske J.R.; Redemann J.; Leblanc S.E.; Segal-Rozenhaimer M.; Pistone K.
发表日期	2021
ISSN	1680-7316
起始页码	4615
结束页码	4635
卷号	21 期号:6
英文摘要	Marine stratocumulus cloud properties over the Southeast Atlantic Ocean are impacted by contact between above-cloud biomass burning aerosols and cloud tops. Different vertical separations (0 to 2000 m) between the aerosol layer and cloud tops were observed on six research flights in September 2016 during the NASA ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) field campaign. There were 30 contact profiles, where an aerosol layer with aerosol concentration (Na) > 500 cm-3 was within 100 m of cloud tops, and 41 separated profiles, where the aerosol layer with Na > 500 cm-3 was located more than 100 m above cloud tops. For contact profiles, the average cloud droplet concentration (Nc) in the cloud layer was up to 68 cm-3 higher, the effective radius (Re) up to 1.3 μ m lower, and the liquid water content (LWC) within 0.01 gm-3 compared to separated profiles. Free-tropospheric humidity was higher in the presence of biomass burning aerosols, and contact profiles had a smaller decrease in humidity (and positive buoyancy) across cloud tops with higher median above-cloud Na (895 cm-3) compared to separated profiles (30 cm-3). Due to droplet evaporation from entrainment mixing of warm, dry free-tropospheric air into the clouds, the median Nc and LWC for contact profiles decreased with height by 21 and 9 % in the top 20 % of the cloud layer. The impact of droplet evaporation was stronger during separated profiles as a greater decrease in humidity (and negative buoyancy) across cloud tops led to greater decreases in median Nc (30 %) and LWC (16 %) near cloud tops. Below-cloud Na was sampled during 61 profiles, and most contact profiles (20 out of 28) were within high-Na (> 350 cm-3) boundary layers, while most separated profiles (22 out of 33) were within low-Na (< 350 cm-3) boundary layers. Although the differences in below-cloud Na were statistically insignificant, contact profiles within lowNa boundary layers had up to 34.9 cm-3 higher Nc compared to separated profiles. This is consistent with a weaker impact of droplet evaporation in the presence of biomass burning aerosols within 100 m above cloud tops. For contact profiles within high-Na boundary layers, the presence of biomass burning aerosols led to higher below-cloud Na (up to 70.5 cm-3) and additional droplet nucleation above the cloud base along with weaker droplet evaporation. Con sequently, the contact profiles in high-Na boundary layers had up to 88.4 cm-3 higher Nc compared to separated profiles. These results motivate investigations of aerosol-cloud-precipitation interactions over the Southeast Atlantic since the changes in Nc and Re induced by the presence of abovecloud biomass burning aerosols are likely to impact precipitation rates, liquid water path, and cloud fraction, and modulate closed-to-open-cell transitions. © 2021 Author(s).
语种	英语
scopus关键词	aerosol; biomass burning; cloud classification; cloud microphysics; concentration (composition); marine environment; stratocumulus; Atlantic Ocean; Atlantic Ocean (Southeast)
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/247026
作者单位	Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma, Norman, OK, United States; School of Meteorology, University of Oklahoma, Norman, OK, United States; Department of Atmospheric Sciences, University of North Dakota, Grand Forks, ND, United States; Department of Atmospheric Sciences, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States; Nasa Ames Research Center, Moffett Field, CA, United States; Bay Area Environmental Research Institute, Moffett Field, CA, United States; Department of Geophysics and Planetary Sciences, Porter School of Environmental and Earth Sciences, Tel Aviv University, Tel Aviv, Israel
推荐引用方式 GB/T 7714	Gupta S.,McFarquhar G.M.,O'Brien J.R.,et al. Impact of the variability in vertical separation between biomass burning aerosols and marine stratocumulus on cloud microphysical properties over the Southeast Atlantic[J],2021,21(6).
APA	Gupta S..,McFarquhar G.M..,O'Brien J.R..,Delene D.J..,Poellot M.R..,...&Pistone K..(2021).Impact of the variability in vertical separation between biomass burning aerosols and marine stratocumulus on cloud microphysical properties over the Southeast Atlantic.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(6).
MLA	Gupta S.,et al."Impact of the variability in vertical separation between biomass burning aerosols and marine stratocumulus on cloud microphysical properties over the Southeast Atlantic".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.6(2021).