2011

The  central  and  western  parts  of  the  State  of  São  Paulo  are  well‐known  for  vast  sugar  cane plantations,  which  during  the  harvest  time  are  traditionally  burnt  about  12  hours  before  manual cutting.  This  procedure  causes  the  release  of  large  quantities  of  aerosols  and  a  variety  of  gases,  which can be observed by IPMet’s radars, located in Bauru and Presidente Prudente, on days with no or little rain. Depending on the distance of these plumes from the radar, they can be detected up to 5 km amsl or more, and are subsequently being transported by winds to other regions. During the dry winter season of 2008, such plumes, attributed to cane fires, were frequently observed by IPMet’s radars and documented in terms of radar reflectivity, time and location during the period 10 th   –  21 st   July  2008.  At  the  same  time,  IPEN’s  Elastic  Backscatter  Lidar  in  São  Paulo  observed layers of aerosols of variable strength and heights above the city. The most significant days, viz. 14 and  15  July  2008  had  been  selected  for  calculating  backward,  as  well  as  forward  trajectories, deploying  the  European  Flextra  3.3  Trajectory  Model,  which  was  initiated  with  ECMWF  historic data with a 0,25o×0,25o grid spacing. The results presented here show an excellent match between the radar‐detected sources of the plumes on 11 th  July 2008 in the central parts of the State and the observations  by  IPEN’s  Lidar  over  Metropolitan  São  Paulo  on  14 th   July  2008,  both  in  terms  of forward  and  backward  trajectories,  as  well  as  their  heights,  with  a  transport  duration  of approximately 70 hours under the prevailing meteorological conditions.

Held, G. ; Landulfo, E. ; Lopes F. J. S. ; ARTETA, ; Marecal V. ; BASSAN, J. M. . Emissions from sugar cane fires in the central & western State of São Paulo and aerosol layers over Metropolitan São Paulo observed by IPEN´s lidar: Is there a connection ?. Optica Pura y Aplicada, v. 44, p. 83-91, 2011.