Vertical profiles of O3 and SO2 in a preserved forest site in Amazonia

Abstract

The Amazon Forest constitutes a complex ecosystem, in which the biosphere and the atmosphere are closely linked. Tropospheric ozone (O3) plays a key role on those interactions, as it is part of the formation mechanism of atmospheric oxidant species in the atmosphere, with impacts to the whole photochemical reactions chain and, consequently, to secondary organic aerosol production from biogenic gaseous precursors. Sulfate dioxide (SO2), produced by the oxidation of biogenic sulfur compounds, also contributes to secondary aerosol formation. In its turn, aerosols interact with solar radiation and change cloud microphysics, with possible impact over climate and hydrological cycle. Thus, feedback and compensation cycles establish, constituting a complex and dynamic system. Anthropogenic activities related to land use change, biomass burning and urbanization disturb the natural ecosystem functioning. To better comprehend the impacts related to these disturbances, it is necessary to determine the relative contribution of sources and sinks of key species, either under undisturbed conditions (wet season) and under disturbed conditions (dry season). This research project proposes measurements of O3 and SO2 vertical profiles in a preserved Amazonian forest site (Floresta Nacional do Tapajós, Pará State), covering part of wet and dry seasons. Turbulent fluxes measurements will be held by scientific collaborators at the same site, as a complement. In this way, a closure for mass balance equations will be obtained, providing the necessary information to evaluate the relative contributions of sources and sinks in the referred forest site. (AU)