Spectral Absorption properties of Aerosols in Amazonia during the Wet and Dry Seasons
J. Vanderlei
Martins, JCET/UMBC - NASA Goddard, martins@climate.gsfc.nasa.gov
(Presenting)
Paulo
Artaxo, USP, artaxo@if.usp.br
Yoram
J.
Kaufman, NASA GSFC, kaufman@climate.gsfc.nasa.gov
The absorption properties of aerosols are responsible for the biggest uncertainties in the climate forcing by aerosols and play major role in both direct and indirect components of the radiative forcing. Large uncertainties commonly found in the standard techniques used today for the measurement of aerosol absorption are addressed in this work and will be discussed. Long term aerosol samples collected in several places in Amazonia were used for the measurement of the aerosol absorption efficiency in the wavelength range between 350-2500 nm. The spectral dependence results show strong evidences of significant absorption by biogenic aerosols, as well as the spectral absorption efficiency for biomass burning and long-range transported dust particles. The absorption spectral dependence was used to characterize the aerosol microphysical model and clearly shows the transition between absorption by very small absorbers, large absorbers, and the combination between small absorbers and larger aerosols. For comparison, results of measurements in samples from several other locations and aerosol types (urban from S. Paulo, US and Israel, dust transported to Israel and US, etc.) will be compared with the Amazonian aerosols.
Submetido por Jose Vanderlei Martins em 25-MAR-2004