Fire influences global ecosystem patterns and processes, including vegetation distribution and structure, the carbon cycle, and climate [1]. The occurrence of fires is marked by a significant inter and intra-annual variability; depending on factors such as weather, climate, vegetation and human activities [2]. The lack of, or differences in reporting fire statistics by national authorities makes a global comparison of fire prone regions difficult. In this sense, the collection of fire occurrence data by remote sensing can provide a more consistent approach to examine global fire patterns.
Global gridded data (1 by 1 degree, see example below) on monthly fire occurrences between 2000 and 2010 taken from [3] and documented in [4] was downscaled to the second administrative level of selected countries (Brazil, Chile, China, India, Indonesia, Philippines, South Africa and Tunisia). In cases where the grid cells containing information on fire counts overlap two or more distinct administrative regions, the allocation of fire numbers is assumed to be linearly proportional to the corresponding forested area of the administrative region that falls within the fire grid cell. Data on forest cover for each grid cell was determined using land-cover data contained in [5] and referent to circa year 2005. Finally, for each administrative region, the average monthly distribution of fires is obtained for the time period 2000-2010.
Figure 1: Cumulative counts of fire activity detected by the Along Track Scanning Radiometer (ATSR) around the world at a resolution of 100 km over 10 years. Adapted from [2].
Due to the short time series of data (10 years), spatial aggregation, and downscaling proceedings, the results of such analysis better illustrate the months in which the majority of forest fires are likely to happen in a particular administrative region, rather than conveying precise numbers on fire statistics. Nevertheless the information can provide a first approximation of the yearly fire patterns and be potentially valuable for data-scarce regions.
References
[1] David M. J. S. Bowman, Jennifer K. Balch, Paulo Artaxo, William J. Bond, Jean M. Carlson, Mark A. Cochrane, Carla M. D Antonio, Ruth S. DeFries, John C. Doyle, Sandy P. Harrison, Fay H. Johnston, Jon E. Keeley, Meg A. Krawchuk, Christian A. Kull, J. Brad Marston, MaxA.Moritz, I. Colin Prentice, Christopher I. Roos, Andrew C. Scott, Thomas W. Swetnam, Guido R. van der Werf, Stephen J. Pyne, Fire in the Earth System, Science, Vol. 324 no. 5926 pp. 481-484 2009. DOI: 10.1126/science.1163886
[2] Krawchuk MA, Moritz MA, Parisien M-A, Van Dorn J, Hayhoe K (2009) Global Pyrogeography: the Current and Future Distribution of Wildfire. PLoS ONE 4(4): e5102. doi:10.1371/journal.pone.0005102
[4] Giglio, L., I. Csiszar and C.O. Justice, Global Distribution and Seasonality of Active Fires as Observed with the Terra and Aqua MODIS Sensors. Journal of Geophysical Research - Biogeosciences, 111, G02016, doi:10.1029/2005JG000142.
