High-Resolution Image

The largest grass fires observed in the history of Texas began on 3/12/06. An ABC news report on 3/17/06 stated that “Since Sunday, the fires have consumed 840,000 acres, killed at least 11 people and forced thousands to evacuate their homes. At least 10,000 cattle and horses have died in the blazes.” The strengths of burning fires and emitted smoke can be estimated from NASA EOS (Earth Observing System) satellite sensors. This true-color Aqua/MODIS image acquired on 3/12/06 shows detected fires on the Texas northern Panhandle fires in red. [Oklahoma is to the north and New Mexico to the west.] The top right inset shows the Aerosol Index measured the same day across the US by the Ozone Monitoring Instrument (OMI) aboard the Aura satellite. Aerosol Index is a measure of atmospheric loading of microscopic particles or aerosols.

Though aerosols may include dust, smoke, urban/industrial/automobile pollution and other forms of airborne particulates, it is obvious that the strong aerosol signal seen across the northern parts of Texas and adjoining locations can be attributed to smoke from the intense fires raging in that region that day. The bottom right inset shows an enlargement of the fire cluster, now including satellite-derived estimates of the Fire Radiative Power (FRP), which is the strength of the radiant energy released by the fire per unit time, for each 1-sq km resolution cell (or pixel) of the MODIS data in units of Mega-Watts (MW). MODIS has a twin sensor onboard another EOS satellite called Terra. This lower right inset shows the fire pixels detected by Terra-MODIS at 18:10 UTC (12:10 PM US Central Time) as little squares, and those detected by Aqua-MODIS 1.5 hours later at 19:45 UTC (1:45 PM US Central Time) as stars. It is amazing how far the fire had spread in just 1.5 hours, under the influence of strong winds.

MODIS on Terra and Aqua can observe most parts of the Earth at least 4 times a day; twice in the daytime and twice at nighttime. Furthermore, sites equipped with MODIS Direct Broadcast (DB) receiving stations can receive the data in real time and generate image and data products such as these in less than one hour. A team of scientists in the Climate & Radiation Branch in collaboration with a team at the US Forest Service (USFS) Fire Sciences Laboratory (FiSL), which operates a DB station, is seeking to develop a system that would enable such powerful fire events and their smoke emission rates to be measured and quantified in near real-time to help fire and air-quality managers in handling such events more efficiently. For instance, a coordinated map of FRP, such as the lower right inset, shows where the fire is strongest, and can be used to plan the optimal deployment of firefighting personnel and equipment for maximum effectiveness.

(Contributed by Charles Ichoku. The true-color image was provided by the MODIS Rapid Response Team. The AI image (upper right inset) was produced by the OMI Science Team and provided by the NASA Earth Observatory Team. The software tool used for visualizing and analyzing the FRP data, as shown in the lower right inset, was developed by Luke Ellison from Bethel University, during his summer internship in July-August 2005 here at NASA Goddard Space Flight Center. Luke is now at the University of Minnesota.)