Characterizing Vegetation Fire Regimes in Brazil Through Adjusted Satellite Fire Detection Data
Wilfrid
Schroeder, IBAMA, wilfrid.schroeder@ibama.gov.br
(Presenting)
Jeffrey
Thomas
Morisette, NASA GSFC, jeff.morisette@nasa.gov
(Presenting)
Louis
Giglio, University of Maryland, giglio@hades.gsfc.nasa.gov
Ivan
Csiszar, University of Maryland, icsiszar@hermes.geog.umd.edu
Douglas
Morton, University of Maryland, morton@geog.umd.edu
Christopher
O.
Justice, University of Maryland, justice@hermes.geog.umd.edu
João
Antonio Raposo
Pereira, IBAMA, jraposo@ibama.gov.br
The role of biomass burning on the terrestrial climate system has been widely studied over the last two decades. In particular, correctly characterizing the frequency and distribution of fire occurrence is a fundamental question for better understanding the resulting environmental impacts of burning. Satellite data have been developed and applied operationally to map vegetation fires over different regions of the globe. Hot spots detected by both the NOAA/AVHRR and NASA/MODIS sensors are used to report clearly apparent annual trends in fire activity through Brazil. However, while relative numbers of spatial and temporal distribution of hot spots correctly describe the situation, absolute values are known to underestimate total number of vegetation fires that occur at the surface. Satellite overpass time, cloud coverage and image acquisition characteristic are the main issues affecting detection performance and thereby the resulting fire statistics. Here we quantify the influence of clouds and viewing geometry on satellite fire detection statistics and develop a straightforward curve-fitting approach to adjust the total fire counts from MODIS-Terra, MODIS-Aqua and NOAA-12 throughout Brazil. The method compensates for day-to-day variation due to cloud cover and changing image acquisition geometry. The results of this adjusted number of fire counts are used to calculate monthly fire counts for each Brazilian state for the past four years to establish Brazilian fire regimes.
Submetido por Wilfrid Schroeder em 18-MAR-2004
Tema Científico do LBA: LC (Mudanças dos Usos da Terra e da Vegetação)