气候变化领域集成服务门户(CCPortal): A weather regime characterisation of winter biomass aerosol transport from southern Africa

CCPortal

DOI	10.5194/acp-21-16575-2021
	A weather regime characterisation of winter biomass aerosol transport from southern Africa
	Gaetani M.; Pohl B.; Alvarez Castro M.D.C.; Flamant C.; Formenti P.
发表日期	2021
ISSN	1680-7316
起始页码	16575
结束页码	16591
卷号	21 期号:21
英文摘要	During austral winter, a compact low cloud deck over the South Atlantic contrasts with clear sky over southern Africa, where forest fires triggered by dry conditions emit large amounts of biomass burning aerosols (BBAs) in the free troposphere. Most of the BBA burden crosses the South Atlantic embedded in the tropical easterly flow. However, midlatitude synoptic disturbances can deflect part of the aerosol from the main transport path towards southern extratropics. In this study, the first objective classification of the synoptic variability controlling the spatial distribution of BBA in southern Africa and the South Atlantic during austral winter (August to October) is presented. By analysing atmospheric circulation data from reanalysis products, a six-class weather regime (WR) classification of the region is constructed. The classification reveals that the synoptic variability is composed of four WRs, representing disturbances travelling at midlatitudes, and two WRs accounting for pressure anomalies in the South Atlantic. The WR classification is then successfully used to characterise the aerosol spatial distribution in the region in the period 2003-2017, in both reanalysis products and station data. Results show that the BBA transport towards southern extratropics is controlled by weather regimes associated with midlatitude synoptic disturbances. In particular, depending on the relative position of the pressure anomalies along the midlatitude westerly flow, the BBA transport is deflected from the main tropical route towards southern Africa or the South Atlantic. Moreover, the WRs accounting for midlatitude disturbances show organised transition sequences, which allow one to illustrate the evolution of the BBA northerly transport across the region in the context of a wave pattern. The skill in characterising the BBA transport shown by the WR classification indicates the potential for using it as a diagnostic/predictive tool for the aerosol dynamics, which is a key component for the full understanding and modelling of the complex radiation-aerosol-cloud interactions controlling the atmospheric radiative budget in the region. © 2021 Marco Gaetani et al.
语种	英语
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/246446
作者单位	Université de Paris, Université Paris Est Creteil, CNRS, LISA, Paris, 75013, France; Scuola Universitaria Superiore IUSS, Pavia, Italy; CRC/Biogéosciences, UMR6282 CNRS, Université de Bourgogne Franche-Comté, Dijon, France; Physical, Chemical and Natural Systems Department, University Pablo de Olavide (UPO), Seville, 41013, Spain; Mediterranean Center of Climate Change (CMCC), Climate Simulation and Prediction Division, Bologna, 40126, Italy; Institut Pierre Simon Laplace, Laboratoire Atmosphères, Milieux, Observations Spatiales, UMR CNRS 8190, Sorbonne Université, Université Versailles Saint Quentin, Paris, France
推荐引用方式 GB/T 7714	Gaetani M.,Pohl B.,Alvarez Castro M.D.C.,et al. A weather regime characterisation of winter biomass aerosol transport from southern Africa[J],2021,21(21).
APA	Gaetani M.,Pohl B.,Alvarez Castro M.D.C.,Flamant C.,&Formenti P..(2021).A weather regime characterisation of winter biomass aerosol transport from southern Africa.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(21).
MLA	Gaetani M.,et al."A weather regime characterisation of winter biomass aerosol transport from southern Africa".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.21(2021).