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Figure 1 – Image of Amazon Basin
There is a very sharp increase in the atmospheric aerosol loading during the biomass burning season, that is observed for all sites. Figures 2, 3 and 4 shows the annual variability of the aerosol loading.
Melina Andrade Paixão1 ([email protected]); Paulo Artaxo¹ ([email protected]); Brent Holben² ([email protected]); Joel Schafer² ([email protected])
Melina Andrade Paixão1 ([email protected]); Paulo Artaxo¹ ([email protected]); Brent Holben² ([email protected]); Joel Schafer² ([email protected])
¹ Institute of Physics, University of São Paulo, São Paulo, Brasil ²NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Aerosol particles in Amazonia have an important role in dynamic processes in the atmosphere. They interact with solar radiation and are responsible for its attenuation, scattering and absorption. On this poster we present the data and analysis of the Aerosol Optical Thickness (AOT) and Single Scattering Albedo (SSA) for six sites in Amazonia: Abracos Hill (Rondonia), Ji Parana (Rondonia), Alta Floresta (Mato Grosso), Balbina (Manaus), Belterra (Santarem), Rio Branco (Acre).Measurements obtained by AERONET – Aerosol Robotic Network, a global network of sunphotometers maintained by NASA and part of LBA – were used. The sunphotometers measure a few key aerosol parameters such as the Aerosol Optical Thickness (AOT) that express the total amount of aerosol particles in the atmospheric column. In this work, we also analyzed the absorption properties of the aerosols, expressed by the Single Scattering Albedo (SSA), a ratio of the scattering coefficient to the extinction coefficient.
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
Abracos Hill
Alta Floresta
Balbina
Belterra
Ji Paraná
Rio Branco
The figure 9 shows the number of hot spots in September/2002, at the peak of the biomass burning season. It is possible to observe that the burning activity is very intensive in Southern Amazon. On the other hand, the Figure 8 shows the same image in April/2002, at the wet season.
The total aerosol loading can also be observed using satellites. Figure 11 shows the monthly average of AOT in September/2002 for South America. The aerosol loading in the Southern Amazon is very high comparing with other sites (AOT ~0.9). The figure 10 shows that the monthly average in the region in April/2002 (wet season) is about 0.2.
Figure 13 shows the median of AOT at dry and wet seasons for all measurements in the sites studied. The periods of measurements were represented in the figure 12. In Ji Parana the median of optical thickness in the biomass burning season is about 286% higher than in the wet season, showing the dramatic increase in atmospheric aerosol loading due to biomass burning emissions. This impact is much smaller in Balbina and Belterra (Santarem). Figure 14 shows the median of SSA, with a clear indication that the biomass burning aerosol scatter more light than the natural biogenic component for all sites. In the wet season, it is surprising to observe how absorbing is the natural biogenic aerosol in Santarem and Rondonia.
Aerosol absorption is a critical optical parameter because it can heats up the atmosphere, changing the temperature vertical profile. Figures 5, 6 and 7 show that the aerosol that causes high AOT (biomass burning) absorbs less than the natural background, with high SSA.
There is a very large increase in aerosol loading due to biomass burning emissions in Amazonia. This increase in aerosols change the radiation balance of the atmosphere, with a significant aerosol radiation forcing. This high aerosol loading can also change cloud microphysics, according to recent LBA results. A surprising result is that the natural biogenic aerosol is more absorbing than biomass burning emissions.
Figure 2 – Time series of AOT in Balbina and Belterra
Figure 5 – Relation between AOT and SSA in Belterra and Balbina
Figure 8 – CPTEC/INPE Hot spots in South America: April/2002
Figure 9 – CPTEC/INPE Hot spots in South America: September/2002
Figure 10 – MODIS Monthly average of AOT in April/2002
Figure 11 – MODIS Monthly average of AOT in September/2002
Figure 3 – Time series of AOT in Abracos Hill and Ji Parana
Figure 4 – Time series of AOT in Rio Branco and Alta Floresta
Figure 14 – Median of Single Scattering Albedo (SSA)
Figure 13 – Median of AOT for the several sites
Figure 12 – Periods of measurements obtained by AERONET
Figure 6 – Relation between AOT and SSA in Rio Branco and Alta Floresta
Figure 7 – Relation between AOT and SSA in Abracos Hill and Ji Parana
We acknowledge CNPq/PADCT Institutos do Milenio program for the support of MilenioLBA.
Abstract ID: 401
