Fernando Morais, University of Sao Paulo, São Paulo, Brazil, Eduardo Landulfo, IPEN/CNEN, Sao Paulo, SP, Brazil, Paulo Artaxo, University of Sao Paulo, Sao Paulo, Brazil, Marco Aurélio Franco, University of Sao Paulo, Institute of Physics, São Paulo, Brazil, Joel Schafer, Science Systems and Applications, Inc., Greenbelt, MD, United States and Brent Holben, NASA Goddard Space Flight Center, Greenbelt, MD, United States