**8. Conclusions**

266 Atmospheric Aerosols – Regional Characteristics – Chemistry and Physics

**Figure 12.** Range corrected backscatter profile at 532 nm for measurements carried out on 23 August 2007 by the MSP-Lidar system between 12:48 to 22:12 (UTC). It can be seen a thin layer of aerosol between 3.5 and 5 km transported from the Midwestern region of the Brazilian territory.

**Figure 13.** Backscatter coefficient profile at 532 nm measured on 23 August 2007 by the MSP-Lidar

On the same day the AERONET sunphotometer installed at MASP obtained AOD values spanning from 0.20 to 0.38, indicating the detection of a high amount of absorbent aerosols loaded in the atmosphere of the MASP. Figure 14 shows the AOD and LR values obtained by the CALIOP sensor aboard the CALIPSO satellite on 23 August 2007, which overpasses the region close to MASP with closest approach of about 80 km. The CALIOP AOD values for this case are spanning from 0.08 to 0.14, which is quite low to the values retrieved by AERONET. Such difference between AOD retrieved by both instruments might have occurred due to the fact that the sunphotometer is installed within the MASP, which is

system between 17:00 to 18:00 (UTC).

In this study, an extensive biomass burning event observed at two different sites in Brazilian territory and track the aerosol transportation from Midwestern to Southeastern region of Brazil have been described. The synergy of MODIS and CALIOP sensor, both aboard of satellites, the AERONET sunphotometer and the elastic backscatter Lidar system measurements allowed to estimate key optical characteristics of the aerosols observed during this event. These results are important for the radiative forcing study in the Brazilian territory and for the study of the effects of certain types of aerosol in the air quality of the megacities such as São Paulo, due to aerosols produced in the MASP as well as those transported from distant regions.

Spatial distribution of fires in the São Paulo State obtained by the NOAA-12 satellite indicates that the winter is the season with the highest number of fire outbreaks. In addition, during the harvest period, which occurs from May to November, the plantation areas are burnt a few hours before the manual cutting, resulting in large quantities of aerosols being emitted into the atmosphere. AOD measurements from MODIS sensor indicate high maximum values during spring and winter (Southeastern dry season). Average of the maximum AOD between 2003 and 2010 was 0.492±0.505, indicating the high variability of the maximum AOD over this region. As in the Brazilian Southeastern region, the large occurrence of higher AOD levels during the dry season for the Midwestern region is basically due to the highest amount of biomass burning loaded in the atmosphere.

Impacts of Biomass Burning in the Atmosphere

of the Southeastern Region of Brazil Using Remote Sensing Systems 269

**Author details** 

*Federal University of Pelotas, UFPEL, Pelotas, Brasil* 

Meteorology at the Federal University of Pelotas.

Engineering 7479: 747905.

Meteorol. Soc. 83: 1771-1790.

*Nuclear and Energy Research Institute, IPEN, São Paulo, Brasil* 

*National Institute for Space Research, INPE, São José dos Campos, Brasil* 

University Press, Cambridge, UK and New York, NY, USA.

The authors wish to acknowledge all the CALIPSO team for data obtained from the NASA Langley Research Center Atmospheric. They also gratefully acknowledge the team of AERONET sunphotometer network, CPTEC/INPE for the active fires and the NOAA Air Resources Laboratory for the provision of the HYSPLIT transport and dispersion model and READY website used in this publication. The first author wishes to acknowledge the financial support of Fundacao para o Amparo da Pesquisa do Estado de Sao Paulo FAPESP under the project number 2011/14365-5. The secong author wish to acknowledge the Research Foundation of the State of Rio Grande do Sul and the post graduate program in

[1] Forster, P., Ramaswamy, V., Artaxo, P., et al. (2007): Changes in Atmospheric Constituents and in Radiative Forcing, in: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge

[2] Landulfo, E., Lopes, F.J.S. (2009) Initial approach in biomass burning aerosol transport tracking with CALIPSO and MODIS satellites, sunphotometer and a backscatter Lidar system in Brazil. (2009) Proceedings of SPIE — The International Society for Optical

[3] Stephens, G.L., D.G. Vane, R.J. Boain, G.G. Mace, K. Sassen, Z. Wang, A.J. Illingworth, E.J. O'Connor, W.B. Rossow, S.L. Durden, S.D. Miller, R.T. Austin, A. Benedetti, C. Mitrescu, and CloudSat Science Team (2002) The CloudSat mission and the A-Train: A new dimension of space-based observations of clouds and precipitation. Bull. Amer.

*São Paulo University, USP, São Paulo, Brasil* 

F. J. S. Lopes and E. Landulfo

G. L. Mariano\*

F. J. S. Lopes

E. V. C. Mariano

**9. References** 

 \*

Corresponding Author

**Acknowledgement** 

One day backtrajectories calculated for 21 August 2007 using the HYSPLIT model indicated that at 3.5, 4.0 and 4.5 km altitude air masses were advected from regions with intensive biomass burning activities in the Midwestern portion of the Brazilian territory. For the biomass burning episode under investigation in the Midwestern region on 21 August 2007, the AOD and LR at 532 nm was calculated using measurements from the CALIOP sensor and the AERONET sunphotometer installed at Campo Grande. The AOD retrieved by CALIOP sensor spanning from 0.30 to 0.65 and the LR was almost constant at 70 sr. The AERONET provides on the same day mean values of AOD and AE of 0.2 and 1.67, respectively, both values higher than the median in the August period (AOD = 0.1980.078 and AE = 1.460.09). Such values correspond to fine mode size distribution and high absorption and extinction aerosol types, which is a strong indication of the predominance of biomass burning aerosols in the atmosphere. MODIS data image also provide a strong indication of biomass burning loaded in the atmosphere in the Midwestern region.

Daytime CALIPSO trajectory on 21 August 2007 together with the HYSPLIT backtrajectories provide evidences that air masses of biomass burning aerosol were transported towards the Southeastern region of Brazilian territory. However, AOD value of 0.10 and LR value of 40-55 sr indicate that those biomass burning aerosol layers have been undergoing an aging process, absorbing moisture from the atmosphere or even mixing with other aerosol types.

Air mass trajectories generated by the HYSPLIT model showed that these biomass burning aerosols were transported from the CG region towards the Metropolitan Area of São Paulo, reaching MASP on 23 August 2007 at an altitude range of 3.5 to 4.5 km. The backscatter coefficient profile retrieved by the MSP-Lidar system showed an atmosphere heavily loaded of aerosol trapped within the PBL and also a distinguishable aerosol layer between 3.5 and 5 km of altitude. LR values retrieved by the MSP-Lidar, reaching maximum values of 66 sr, are in agreement with LR values of 55 sr signed by the CALIOP sensor. This LR value of 55 sr indicates the presence of polluted dust aerosol type instead of biomass burning type, though. However, it needs to be taken into account that the closest approach of the CALIPSO satellite was 80 km eastern of the MSP-Lidar site, which can lead to the fact that both instruments were not probing the same air mass parcels. Furthermore, the LR values retrieved from MSP-Lidar system in the whole period of time indicate the presence of several amount of aerosols present in the atmosphere of São Paulo, which can disguise the individual effect of the optical properties from biomass burning aerosols, which may have had their optical properties altered due to transport and aging processes [37].

This case study shows that the synergy and combination of analysis using several remote sensing instruments, whether passive or active, results in a better understanding of the aerosol optical properties in the atmosphere. Furthermore, these results show that aerosols produced in different regions can be transported by long-range distances. In this sense, megacities such as the Metropolitan Area of São Paulo, which have a large number of local aerosol sources is subject to the influence of aerosol pollution produced by remote sources.
