FEATURE - NASA climate satellite keeping tabs on wildfires
Date: 31-Aug-01
Country: USA
Author: Amy Kane
NASA's Terra satellite, with sensors designed to detect pollution, deforestation and urban growth, turns out to be very good at plotting smoke, hot spots and previously burnt areas.
Circling 438 miles (705 km) above the Earth, Terra can tell firefighters twice a day where blazes are, their direction and the degree of destruction they are leaving behind.
Tested last September in the decade's worst wildfire season, the system has been refined and put to regular use this month as fires have raged in California, Oregon and Idaho.
Rick Ochoa, a meteorologist at the National Fire Information Center in Boise, Idaho, uses maps from Terra almost daily to advise fire directors where the next hot spots will be and how to direct resources.
"I can see the fires overlaid on the terrain. I'm able to see past fires. It's a great timesaver," Ochoa said.
Terra scans the area in greater detail and more frequently than existing satellites, said Ron Sohlberg, a University of Maryland geography researcher who helped develop the system.
One of five modules on Terra called a moderate-resolution spectroradiometer (MODIS) scans the planet in 1,450-mile (2,330 km) wide strips. Scientists can plot fires within a half mile (1 km).
STRATEGIC TOOL
"It's fairly coarse," said Mark Finco, a U.S. Forest Service senior scientist who helps develop the maps. "We're really providing a strategic tool. This cannot be used to send people up a hill."
MODIS is more sensitive to high-level heat than AVHRR, a National Oceanic and Atmospheric Administration weather satellite, and operates more frequently than Landsat, a NASA satellite that takes a portrait of the globe 30 times more detailed than Terra's every 16 days.
Ochoa said he still uses these other satellites and weather reports to show where dry terrain might combine with lightening storms to ignite fires.
For battling individual fires, the Forest Service and the Bureau of Land Management use heat sensors on planes and information provided by rangers on the ground and in lookout towers.
When Terra was launched in December 1999 it could pinpoint fires but it could not disperse that information quickly.
NASA and University of Maryland researchers developed a computer program to sort data broadcast by Terra, draw maps based on the data and locate active fires.
"The maps have the previous days fires in yellow and the active fires outlined in red. It's easy to see which way fires are moving," Sohlberg said.
The maps also show the proximity of large fires to roads and airports, an important detail for firefighters trying move water, machinery and firefighters to the fires.
After the embers have died out, scientists continue to use Terra's data to create "burn severity maps."
Scientists can compare before and after maps of an area taken by Terra and determine how to prevent erosion and rehabilitate the land for plants and wildlife.
Producing the maps took a day last year but now takes only four hours. That time will be shortened further after the Forest Service opens a new processing center in October.
Ochoa said speedier access to data will help plan preemptive strikes on dry territory.
"If we can get enough resources there ahead of the fires, we're not going to catch every fire, but we'll catch a number of them while they're still small," he said.