Journal article
Heterogeneous processes involving nitrogenous compounds and Saharan dust inferred from measurements and model calculations
Journal of Geophysical Research: Atmospheres, Vol.106(D12), pp.12559-12578
06/27/2001
DOI: 10.1029/2000JD900778
Abstract
Experimental data on aerosol chemical composition and gaseous concentrations in various African ecosystems have been obtained under the IGAC DEBITS AFRICA (IDAF) program. In this paper, data covering a complete wet and dry season (1996 and 1998) in the semiarid savanna of the Sahelian region of Niger are presented. The analysis of the aerosol chemical composition and the gas phase concentrations at the Banizoumbou station indicates two strong signatures: a nitrogenous component composed of nitric acid, ammonia, particulate ammonium, and nitrates; and a terrigenous component originating from semiarid and desert soils (calcium, carbonates, magnesium, potassium, sulfate). To further investigate the interactions between gas and particles and to help interpret the IDAF experimental data, these data are analyzed using a gas aerosol equilibrium model (Simulating Composition of Atmospheric Particles at Equilibrium (SCAPE)). The model is found to accurately represent the mean aerosol composition for the dry and the wet season of the studied region. It is found that heterogeneous processes involving terrigenous compounds are important and play a major role in partitioning semivolatile species, such as nitric acid, between the gas and aerosol phases. The important role of these heterogeneous processes in the atmospheric chemistry in the Sahelian region is discussed. To compare results obtained in the semiarid savanna of Niger and other African ecosystems, SCAPE model is also applied to humid savanna and forest using IDAF and Experiment for Regional Sources and Sinks of Oxidants (EXPRESSO) measurements.
Details
- Title: Subtitle
- Heterogeneous processes involving nitrogenous compounds and Saharan dust inferred from measurements and model calculations
- Creators
- C Galy‐LacauxG. R CarmichaelC H SongJ. P LacauxH Al OurabiA. I Modi
- Resource Type
- Journal article
- Publication Details
- Journal of Geophysical Research: Atmospheres, Vol.106(D12), pp.12559-12578
- DOI
- 10.1029/2000JD900778
- ISSN
- 0148-0227
- eISSN
- 2156-2202
- Number of pages
- 20
- Language
- English
- Date published
- 06/27/2001
- Academic Unit
- Civil and Environmental Engineering; Nursing; Chemical and Biochemical Engineering
- Record Identifier
- 9984003940502771
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