DOI: 10.1016/j.atmosenv.2015.04.064
Scopus记录号: 2-s2.0-84930629251
论文题名: Precipitation chemistry and wet deposition in a remote wet savanna site in West Africa: Djougou (Benin)
作者: Akpo A ; B ; , Galy-Lacaux C ; , Laouali D ; , Delon C ; , Liousse C ; , Adon M ; , Gardrat E ; , Mariscal A ; , Darakpa C
刊名: Atmospheric Environment
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2015
卷: 115 起始页码: 110
结束页码: 123
语种: 英语
英文关键词: Chemical composition
; Neutralization factor
; Precipitation chemistry
; Wet deposition
Scopus关键词: Animals
; Calcium
; Carbonates
; Chemical analysis
; Chlorine
; Chromatography
; Deposition
; Ecology
; Ecosystems
; Forestry
; Ion chromatography
; Ions
; Magnesium
; Precipitation (meteorology)
; Rain
; Chemical compositions
; Collection efficiency
; International program
; Neutralization factor
; Nitrate concentration
; Nitrogenous compounds
; Precipitation chemistry
; Wet deposition
; pH
; ammonia
; biofuel
; calcium ion
; carbonic acid derivative
; carboxylic acid
; inorganic compound
; magnesium ion
; mineral
; nitrate
; nitrogen derivative
; organic compound
; potassium
; rain
; sodium chloride
; chemical composition
; concentration (composition)
; neutralization
; pH
; precipitation (climatology)
; precipitation quality
; savanna
; spatiotemporal analysis
; transect
; wet deposition
; aerosol
; Article
; Benin
; biomass
; Central Africa
; Central African
; chemical composition
; combustion
; concentration (parameters)
; domestic animal
; ecosystem
; ion pair chromatography
; nonhuman
; pH
; precipitation
; priority journal
; rural area
; savanna
; season
; wet deposition
; Chemical Composition
; Deposition
; Neutralization
; Precipitation
; Banizoumbou
; Benin [West Africa]
; Cameroon
; Cote d'Ivoire
; Djougou
; Donga
; Dosso
; Lamto
; Niger [West Africa]
; Animalia
Scopus学科分类: Environmental Science: Water Science and Technology
; Earth and Planetary Sciences: Earth-Surface Processes
; Environmental Science: Environmental Chemistry
英文摘要: In the framework of the IDAF (IGAC/DEBITS/AFrica) international program, this study aims to study the chemical composition of precipitation and associated wet deposition at the rural site of Djougou in Benin, representative of a West and Central African wet savanna. Five hundred and thirty rainfall samples were collected at Djougou, Benin, from July 2005 to December 2009 to provide a unique database. The chemical composition of precipitation was analyzed for inorganic (Ca2+, Mg2+, Na+, NH4+, K+, NO3-, Cl-, SO42-) and organic (HCOO-, CH3 COO-, C2 H5 COO-, C2 O4 2-) ions, using ion chromatography. The 530 collected rain events represent a total of 5706.1mm of rainfall compared to the measured pluviometry 6138.9mm, indicating that the collection efficiency is about 93%. The order of total annual loading rates for soluble cations is NH4+>Ca2+>Mg2+>K+. For soluble anions the order of loading is carbonates>HCOO->NO3->CH3 COO->SO42->Cl->C2 O4 2->C2 H5 COO-. In the wet savanna of Djougou, 86% of the measured pH values range between 4.7 and 5.7 with a median pH of 5.19, corresponding to a VWM (Volume Weighed Mean) H+ concentration of 6.46μeq·L-1. This acidity results from a mixture of mineral and organic acids. The annual sea salt contribution was computed for K+, Mg2+, Ca2+ and SO42- and represents 4.2% of K+, 41% of Mg2+, 1.3% of Ca2+, and 7.4% of SO42-. These results show that K+, Ca2+, SO42-, and Mg2+ were mainly of non-marine origin. The marine contribution is estimated at 9%. The results of the chemical composition of rainwater of Djougou indicates that, except for the carbonates, ammonium has the highest VWM concentration (14.3μeq·L-1) and nitrate concentration is 8.2μeq·L-1. The distribution of monthly VWM concentration for all ions is computed and shows the highest values during the dry season, comparing to the wet season. Identified nitrogenous compound sources (NOx and NH3 ) are domestic animals, natural emissions from savanna soils, biomass burning and biofuel combustions. The second highest contribution is the calcium ion (13.3μeq·L-1), characteristic of dust aerosols from terrigenous sources, Calcium contributes up to 46% of the precipitation chemistry in Djougou. Finally, these results are compared to those obtained for other selected African sites representative of other main natural ecosystems: dry savanna and forest. The study of the African ecosystem transect indicates a pH gradient with more acidic pH in the forested ecosystem. Nitrogenous contribution to the chemical composition of rain in Lamto, wet savanna, (24%) is equivalent to the one estimated in Djougou (24%). The last contribution concerns organic acidity, which represents 7% of total ionic content of precipitation at Djougou. The relative particulate contribution PC and the relative gaseous contribution GC are calculated using the mean chemical composition measured in Djougou for the studied period. The comparison with other African sites gives 40% and 43% PC in wet savannas of Lamto (CÔte d'Ivoire) and Djougou (Benin) respectively, 20% PC in the equatorial forest of Zoetele (Cameroon) and 80% PC in dry savanna of Banizoumbou (Niger). The results shown here indicate the existence of a North-South gradients of organic, marine, terrigenous and nitrogenous contributions along the transect in West and Central Africa. © 2015. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/81640
Appears in Collections: 气候变化事实与影响
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作者单位: Département de Physique, Université d'Abomey Calavi, BP 526, Cotonou, Benin; Laboratoire d'Aérologie, UMR CNRS/UPS 5560, Toulouse, France; Département de physique, Université Abdou Moumouni, Faculté des Sciences, Niamey, Niger; Laboratoire de Physique de l'atmosphère, Université de Cocody, Abidjan, Cote d'Ivoire; Institut de Recherche pour le Développement (IRD), Benin
Recommended Citation:
Akpo A,B,, Galy-Lacaux C,et al. Precipitation chemistry and wet deposition in a remote wet savanna site in West Africa: Djougou (Benin)[J]. Atmospheric Environment,2015-01-01,115