Seasonal aspects of atmospheric aerosol optical properties over South America from AERONET measurements
Carlos
Alberto
Pires Jr, Institute of Physics, University of São Paulo, Brazil, capjr@if.usp.br
(Presenting)
Paulo
Artaxo, Institute of Physics, University of São Paulo, Brazil, artaxo@if.usp.br
Brent
Holben, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA, brent@aeronet.gsfc.nasa.gov
Joel
Schafer, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA, joel.schafer@gsfc.nasa.gov
Several works have been conducted over the last years in order to study the optical properties of biomass burning aerosols in the Amazon Basin, and important results were obtained about its effects on local and regional climate. In other hand, more and more transport simulations have led researchers to ask about the conditions and effects of biomass burning aerosol after mid and long range transport over South America. The present study analyzed data from 10 AERONET (Aerosol Robotic Network) sites, distributed over approximately 70% of South America area, from Balbina (01°S,59°W) to Puerto Madryn (42°S,65°W). High significant seasonality was observed, with all sites showing important increases in the values of Aerosol Optical Thickness (AOT), that express the total aerosol loading in the atmosphere, from August to November. This period represents the dry season for most part of the continent, historically related to high levels of biomass burning activities, and the results obtained show that this seasonality appears even for sites located more than 1000 km away from the burning activities regions. The increase on AOT values during dry season varied from 75% (Alta Floresta) to 15% (Puerto Madryn). The statistical analysis applied on AOT were extended for other optical properties, mainly related to particle size, solar radiation absorption and total precipitable water along the atmosphere column. These properties allowed observing seasonality of meteorological parameters of the atmosphere, and made possible to differentiate the characteristics of natural background aerosol from that influenced by biomass burning emissions.
Submetido por Carlos Alberto Pires Jr em 19-MAR-2004