气候变化领域集成服务门户(CCPortal): The potential of increasing man-made air pollution to reduce rainfall over southern West Africa

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DOI	10.5194/acp-21-35-2021
	The potential of increasing man-made air pollution to reduce rainfall over southern West Africa
	Pante G.; Knippertz P.; Fink A.H.; Kniffka A.
发表日期	2021
ISSN	1680-7316
起始页码	35
结束页码	55
卷号	21 期号:1
英文摘要	Southern West Africa has one of the fastest-growing populations worldwide. This has led to a higher water demand and lower air quality. Over the last 3 decades, most of the region has experienced decreasing rainfall during the little dry season (LDS; mid-July to end of August) and more recently also during the second rainy season (SRS; September-October), while trends during the first rainy season (FRS; mid-May to mid-July) are insignificant. Here we analyse spatio-Temporal variations in precipitation, aerosol, radiation, cloud, and visibility observations from surface stations and from space to find indications for a potential contribution of anthropogenic air pollution to these rainfall trends. The proposed mechanism is that the dimming of incoming solar radiation by aerosol extinction contributes to reducing vertical instability and thus convective precipitation. To separate a potential aerosol influence from large-scale climatic drivers, a multilinear-regression model based on sea-surface temperature (SST) indices is used. During both LDS and SRS, weakly statistically significant but accelerating negative rainfall trends unrelated to known climatic factors are found. These are accompanied by a strong increase in pollution over the upstream tropical Atlantic caused by fire aerosol from Central Africa, particularly during the LDS. Over southern West Africa, no long-Term aerosol records are available, inhibiting a direct quantification of the local man-made effect. However, significant decreases in horizontal visibility and incoming surface solar radiation are strong indicators for an increasing aerosol burden, in line with the hypothesized pollution impact on rainfall. The radiation trend is further enhanced by an increase in low-level cloudiness. The large spatial extent of potentially aerosol-related trends during the LDS is consistent with the stronger monsoon flow and less wet deposition during this season. Negligible aerosol impacts during the FRS are likely due to the high degree of convective organization, which makes rainfall less sensitive to surface radiation. The overall coherent picture and the accelerating trends-some of which are concealed by SST effects-should alarm policymakers in West Africa to prevent a further increase in air pollution as this could endanger water supply and food and energy production for a large and growing population. © 2021 Copernicus GmbH. All rights reserved.
语种	英语
scopus关键词	aerosol; air quality; atmospheric pollution; cloud microphysics; policy making; pollution monitoring; precipitation intensity; rainfall; sea surface temperature; solar radiation; spatial variation; temporal variation; water supply; Central Africa; West Africa
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/247246
作者单位	Institute of Meteorology and Climate Research, Department Troposphere Research (IMK-TRO), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Str. 1, Karlsruhe, 76131, Germany; German Meteorological Service, Frankfurter Str. 135, Offenbach am Main, 63067, Germany; German Meteorological Service-Research Centre Human Biometeorology, Stefan-Meier-Str. 4, Freiburg, 79104, Germany
推荐引用方式 GB/T 7714	Pante G.,Knippertz P.,Fink A.H.,et al. The potential of increasing man-made air pollution to reduce rainfall over southern West Africa[J],2021,21(1).
APA	Pante G.,Knippertz P.,Fink A.H.,&Kniffka A..(2021).The potential of increasing man-made air pollution to reduce rainfall over southern West Africa.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(1).
MLA	Pante G.,et al."The potential of increasing man-made air pollution to reduce rainfall over southern West Africa".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.1(2021).