NITROGEN COMPOUNDS EMISSION AND DEPOSITION IN WEST AFRICAN DRY AND WET SAVANNA: INTERANNUAL VARIABILITY

摘要

The purpose of this study is to estimate the impact of the interannual variability in precipitations on the interannual variability in emission and deposition of nitrogen compounds in West Africa. Dry and wet deposition fluxes are calculated from surface measurements of NO_2, HNO_3 and NH_3 concentrations (from passive samplers) and simulated deposition velocities, and wet deposition fluxes are calculated from NH_4~+ and NO_3~- concentration in samples of rain. Emission fluxes are evaluated including simulated NO biogenic emission from soils, emissions of NO_x and NH_3 from biomass fires, and volatilization of NH_3 from animal excreta. This study uses original and unique data from remote and hardly-ever-explored regions. Due to the scarcity of available data on the African continent, it is of the first importance to combine data from different origins (surface measurements, satellite and modelling).