Several active fire signals in Central America are recorded by OSEI with the NOAA AVHRR and GOES Sensor on 13 April 1999.
Fig.1. and Fig.2. NOAA image of vegetation fires in Mexico, Honduras and Guatemala, and several other countries of Central America on 13 April 1999
(Source: NOAA http://www.osei.noaa.gov/)
In Fig.1. heat signatures (red spots), at least some of which are due to fires burning in Mexico, Guatemala and Honduras. Some caution must be exercised in identifying all of the hot spots as fires because solar-heating of the surface easily saturates Channel 3 of the AVHRR. The presence of smoke (blue haze) in the hot spot area indicates that some of the hot spots are fire-related.
Fig.2. shows heat signatures (bright white spots) from areas of fire burning in Mexico and Central America. Because of the lower resolution, hot spots in GOES imagery can be more confidently identified as fire-related since solar-heated ground often appears as broad areas of white rather than as pixels of bright white.
Most of the fires in Central America must be seen in the context of intensive land development. Fire is used as a tool in forest conversion. This is done by small farmers as well as large agro-industrial companies. The careless use of fire often allow the “prescribed” burnings to escape and become forest fires in the adjacent forests. Almost all fires inCentral America are human-caused, natural fires play a minor role in the tropical rain forest of Central America.
Under normal weather conditions the primary forest in the humid tropics does not catch fire. The hydrological cycle in the closed forests produces a very humid microclimate where unfavourable conditions for forest fire exist. But in forests where selective logging already took place the former closed canopy is disturbed. This allows more light to penetrate through the canopy and thereby changing the energy balance within the forest – the forest becomes more susceptible to drought and consequently to fire.