气候变化领域集成服务门户(CCPortal): Above-cloud aerosol optical depth from airborne observations in the southeast Atlantic

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DOI	10.5194/acp-20-1565-2020
	Above-cloud aerosol optical depth from airborne observations in the southeast Atlantic
	Leblanc S.E.; Redemann J.; Flynn C.; Pistone K.; Kacenelenbogen M.; Segal-Rosenheimer M.; Shinozuka Y.; Dunagan S.; Dahlgren R.P.; Meyer K.; Podolske J.; Howell S.G.; Freitag S.; Small-Griswold J.; Holben B.; Diamond M.; Wood R.; Formenti P.; Piketh S.; Maggs-Kölling G.; Gerber M.; Namwoonde A.
发表日期	2020
ISSN	1680-7316
起始页码	1565
结束页码	1590
卷号	20 期号:3
英文摘要	The southeast Atlantic (SEA) region is host to a climatologically significant biomass burning aerosol layer overlying marine stratocumulus. We present the first results of the directly measured above-cloud aerosol optical depth (ACAOD) from the recent ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) airborne field campaign during August and September 2016. In our analysis, we use data from the Spectrometers for Sky-Scanning Sun-Tracking Atmospheric Research (4STAR) instrument and found an average ACAOD of 0.32 at 501 nm (range of 0.02 to 1.04), with an average Ångström exponent (AE) above clouds of 1.71. The AE is much lower at 1.25 for the full column (including below-cloud-level aerosol, with an average of 0.36 at 501 nm and a range of 0.02 to 0.74), indicating the presence of large aerosol particles, likely marine aerosol, in the lower atmospheric column. The ACAOD is observed from 4STAR to be highest near the coast at about 12 S, whereas its variability is largest at the southern edge of the average aerosol plume, as indicated by 12 years of MODIS observations. In comparison to MODISderived ACAOD and long-term fine-mode plume-average AOD along a diagonal routine track extending out from the coast of Namibia, the directly measured ACAOD from 4STAR is slightly lower than the ACAOD product from MODIS. The peak ACAOD expected from MODIS AOD retrievals averaged over a long term along the routine diagonal flight track (peak of 0.5) was measured to be closer to coast in 2016 at about 1.5-4 E, with 4STAR ACAOD av erages showing a peak of 0.42. When considering the full observation set over the SEA, by spatially binning each sampled AOD, we obtain a geographically representative mean ACAOD of 0.37. Vertical profiles of AOD showcase the variability in the altitude of the aerosol plume and its separation from the cloud top. We measured larger AOD at a high altitude near the coast than farther from the coast, while generally observing a larger vertical gap farther from the coast. Changes in AOD with altitude are correlated with carbon monoxide, a gas tracer of the biomass burning aerosol plume. Vertical extent of gaps between aerosol and cloud show a wide distribution, with a near-zero gap being most frequent. The gap distribution with longitude is observed to be largest at about 7 E, farther from coast than expected from previous studies. © 2020 Author(s).
语种	英语
scopus关键词	aerosol; airborne survey; atmospheric plume; marine atmosphere; MODIS; optical depth; vertical profile; Atlantic Ocean; Atlantic Ocean (Southeast); Namibia
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/141561
作者单位	Bay Area Environmental Research Institute, Moffett Field, CA, United States; NASA Ames Research Center, Moffett Field, CA, United States; University of Oklahoma, Norman, OK, United States; Department of Geophysics and Planetary Sciences, Porter School of the Environment and Earth Sciences, Tel-Aviv University, Tel-Aviv, Israel; Universities Space Research Association, Columbia, MD, United States; California State University Monterey Bay, Seaside, CA, United States; NASA Goddard Space Flight Center, Greenbelt, MD, United States; University of Hawai'i at Ma noa, Honolulu, HI, United States; University of Washington, Seattle, WA, United States; LISA, UMR CNRS 7583, Université Paris-Est Créteil et Université Paris Diderot, Institut Pierre Simon Laplace, Créteil, France; North-West University, Potchefstroom, South Africa; Gobabeb Research and Training Center, Gobabeb, Namibia; Sam Nujoma Marine and Coastal Resources Research Centre (SANUMARC), University of Namibia, Henties Bay, Namibia
推荐引用方式 GB/T 7714	Leblanc S.E.,Redemann J.,Flynn C.,et al. Above-cloud aerosol optical depth from airborne observations in the southeast Atlantic[J],2020,20(3).
APA	Leblanc S.E..,Redemann J..,Flynn C..,Pistone K..,Kacenelenbogen M..,...&Namwoonde A..(2020).Above-cloud aerosol optical depth from airborne observations in the southeast Atlantic.Atmospheric Chemistry and Physics,20(3).
MLA	Leblanc S.E.,et al."Above-cloud aerosol optical depth from airborne observations in the southeast Atlantic".Atmospheric Chemistry and Physics 20.3(2020).