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DOI	10.1016/j.atmosres.2020.105423
	Source contributions in precipitation chemistry and analysis of atmospheric nitrogen deposition in a Sahelian dry savanna site in West Africa
	Laouali D.; Delon C.; Adon M.; Ndiaye O.; Saneh I.; Gardrat E.; Dias-Alves M.; Tagesson T.; Fensohlt R.; Galy-Lacaux C.
发表日期	2021
ISSN	0169-8095
卷号	251
英文摘要	Experimental data on precipitation chemistry were collected at a semi-arid savanna in Senegal (Dahra) in 2013, 2014 and 2017. The chemical composition of precipitation was analyzed for inorganic and organic ions, using ionic chromatography. The pH values of precipitation range from 4.50 to 8.50 with 89% of the samples having basic pH. The composition of precipitation was controlled by four source contributions: marine, terrigenous, biogenic, and organic acids emissions from vegetation. The terrigenous contribution was the highest accounting for 42% of the total annual Volume Weighted Mean ionic concentrations, due to the proximity of the Saharan desert, followed by the marine source representing 36%, due to the location of Dahra close to the Atlantic Ocean. Nitrogenous (N) contribution represents 16% of the mean annual total ionic charge, from biogenic sources and livestock crossing the site all year round. Finally, the lowest contribution is from organic acidity (5%), due to the low density of vegetation especially during the dry season. Wet deposition fluxes in Dahra for all compounds show larger values than at other Sahelian savanna sites. Dry N deposition in Dahra was also estimated by inferential method using gas concentration measurements and modeled dry deposition velocities. The total N deposition fluxes (wet plus dry) range from 3.80 to 4.81 kgN ha−1 yr−1, comparable to fluxes at other semi-arid savannas in Niger and Mali. Wet deposition contributed with 37–53% of the total N flux, suggesting that wet N deposition is equally important to dry deposition fluxes for direct N loading to savanna ecosystems in the Sahel, with a large contribution of reduced compounds. This study shows that Dahra presents a precipitation chemistry composition with characteristics close to those from other Sahelian sites, with however the specificity of being more influenced by the proximity of the Atlantic ocean and the presence of livestock year round. © 2020 The Authors
英文关键词	Dry deposition; Nitrogen; Precipitation chemistry; Semi-arid climate; West Africa; Wet deposition
语种	英语
scopus关键词	Agriculture; Atmospheric chemistry; Ecosystems; Nitrogen; Vegetation; Atmospheric nitrogen deposition; Chemical compositions; Dry deposition fluxes; Dry deposition velocities; Gas concentration measurement; Ionic concentrations; Precipitation chemistry; Source contributions; Chromatography; chemical composition; dry deposition; experimental study; nitrogen; pH; precipitation (chemistry); savanna; semiarid region; wet deposition; Eritrea; Northern Red Sea; Sahel [Northern Red Sea]; Senegal
来源期刊	Atmospheric Research
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/162128
作者单位	Université Abdou Moumouni, Faculté des Sciences et Techniques, Niamey, BP 10662, Niger; Laboratoire d'Aérologie, Université de Toulouse, Toulouse, France; Laboratoire de Physique de l'Atmosphère, Université Felix Houphouët Boigny, Abidjan, Cote d'Ivoire; Centre de Recherches Zootechniques de Dahra, Institut Sénégalais de Recherches Agricoles, Dahra, Senegal; Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark; Department of Physical Geography and Ecosystem Sciences, Lund University, Sweden; Laboratoire des Sciences et Techniques de l'Environnement, Université Jean Lorougnon Guédé, Daloa, Cote d'Ivoire
推荐引用方式 GB/T 7714	Laouali D.,Delon C.,Adon M.,et al. Source contributions in precipitation chemistry and analysis of atmospheric nitrogen deposition in a Sahelian dry savanna site in West Africa[J],2021,251.
APA	Laouali D..,Delon C..,Adon M..,Ndiaye O..,Saneh I..,...&Galy-Lacaux C..(2021).Source contributions in precipitation chemistry and analysis of atmospheric nitrogen deposition in a Sahelian dry savanna site in West Africa.Atmospheric Research,251.
MLA	Laouali D.,et al."Source contributions in precipitation chemistry and analysis of atmospheric nitrogen deposition in a Sahelian dry savanna site in West Africa".Atmospheric Research 251(2021).