Physical and chemical interactions between the biosphere and the atmosphere of Amazonia in LBA experiment

Abstract

This proposal implements studies on the physical and chemical interactions at the biosphere-atmosphere interface in Amazonia. It is an integrated part of the Large Scale Biosphere-Atmosphere Experiment in Amazonia - LBA. It is one of the five components of LBA: 1) Physical climate; 2) Carbon cycle and biogeochemistry; 3) Chemistry and physics of the atmosphere; 4) Hydrology and water chemistry; 5) Numerical Modeling.We are proposing to install and operate continuously for four years three atmospheric monitoring stations at: 1) Tapajós National Forest; 2) Manaus; 3) São Gabriel da Cachoeira. These sites will have towers from the LBA experiment. At these sampling stations we will measure several trace gases, including CO2, CH4, N20, CO, VOCS (Volatile Organic Carbon compounds), hydrocarbons, NOx, NOy and Ozone. Aerosol particles will be studied in detail, with measurements of aerosol composition and ionic content, size distribution and optical properties, as well as organic and elemental carbon. In addition, precipitation composition in terms of trace elements, ionic content, dissolved and total carbon will be measured, in order to obtain the wet deposition fluxes of essential nutrients. Continuos measurements of aerosol optical thickness with sun-photometers will allow a detailed study of the influence of aerosol particles on the atmospheric radiation budget. Intensive field studies will be performned twice a year, in the dry and wet season. At these intensive campaigns, gaseous compounds and aerosol properties that are difficult to measure continuously will be determined. These campaigns will be runned in parallel with Europeans and American groups that will take part in LBA, with the objective of to assimilate in Brazil the large amount of new knowledge that will be generated. Large-scale experiments using aircraft will allow basin-wide studies on the atmospheric composition and properties. The atmospheric chemistry of VOCs, Nox and several oxidants will be studied from the pointo of view of photochemistry processes and atmospheric carbon cycling. Radiative transfer models will study the relationship between aerosols and the radiative balance in the dry and wet seasons. Biochemical models will work with nutrient pools and fluxes, and will study the dry and wet deposition fluxes of essential nutrients. Chemical-dynamic transport models will be developed for the Amazon Basin, to integrate the atmospheric chemistry measurements with the large-scale transport. (AU)