Several active fire signals are recorded by OSEI with the NOAA AVHRR Sensor on 4 May 1999 in Mexico and Central America.
Fig.1. and Fig.2. NOAA images of smoke from areas of vegetation fires in Mexico and Central America on 4 May 1999 (Source: NOAA http://www.osei.noaa.gov/)
In Figure 1 two images of fire-related phenomena from areas of fire burning in Mexico and Central America. In the top image, smoke can be seen streaming northward from Mexico over the Gulf of Mexico. The smoke is being carried into the southern United States by strong winds flowing around a storm system producing severe weather in the that region. The right satallite image (Fig. 2) shows heat signatures and smoke from the areas of fire mentioned in the left picture.
Fig.3. NOAA image of vegetation fires and smoke plumes extending from Ontario, Canada over the United States to Central America on 4 May 1999 (Source: NOAA http://www.osei.noaa.gov/)
South of the large thunderstorms along the Gulf Coast is a brown, hazy area which is smoke from fires in Mexico and Central America. The southerly flow, which is fueling the developing storms by carrying low-level moisture off the Gulf of Mexico, is also transporting smoke from the central Gulf of Mexico over the Gulf Coast states. Finally, notice the yellow cone-shaped areas north of the Great Lakes in Ontario, Canada. These are dense plumes of smoke extending to the north from areas of fire burning in this region (Fig. 3).
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.