[Summary adopted from the online dataset description]
The TRMM/TSDIS Fire Products include two parts:
1.The Daily hot spot image shows the geographic positions of global fire pixels daily. Typically, a pixel is identified as a fire pixel if the VIRS channel 3 brightness temperature is above 320 K and temperature difference between channel 3 and channel 4 is above 20 K in daytime. In nighttime, ... the channel 3 brightness temperature is required to be above 315 K and the temperature difference between channel 3 and channel 4 to be above 15 K. The bare ground pixels and sun glint pixels are excluded in the Daily hot spot image. ftp://ftp-tsdis.gsfc.nasa.gov/pub/yji/DAILY/
2.The Monthly product is a 0.5 latitude by 0.5 longitude composite map of fire counts for each month beginning January 1998. The Data Source File of the monthly product lists necessary information of all the hot spot pixels of the month. The information includes: date, granule number, solar zenith angle, latitude, longitude, land type, reflectance of channels 1&2, brightness temperatures of channels 3 &4, difference of channel 3 brightness temperatures and channel 4 brightness temperature and environmental channel 3 &4 brightness temperatures. The sunglint pixels are not excluded in the Data Source File. ftp://ftp-tsdis.gsfc.nasa.gov/pub/yji/MONTHLY/
NOTE: the data source files are normal text files that have been compressed with gzip.
A 4.4 square kilometer fire product is also available from NASA's Earth Observatory at: http://earthobservatory.nasa.gov/Observatory/Datasets/fires.trmm.html