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Satellite Imagery Aids Early Detection of US Wildfires - 2002-08-07


This year has been one of the worst on record for forest fires in the United States. In order to stay one step ahead of the blazes, firefighters have deployed an array of fire-detection technologies on the ground and in the air. These technologies can give firefighters additional information about exactly where the most dangerous wildfires are, and where they might be headed.

There are two basic methods of fire detection available to firefighters today. One is land-and-helicopter-based infrared technology, in which heat sensitive imagery is obtained directly from the site of a suspected forest fire. The other is space-based fire detection, an increasingly common method of spotting fires that relies on remote imagery from earth-orbiting satellites. Some of these satellites are geostationary, meaning that they orbit over the same spot of the earth constantly, and some are polar-orbiting satellites.

At NOAA, the National Oceanographic and Atmospheric Administration, in Maryland, new satellite information arrives every 30 minutes. Most of the data NOAA analyzes is weather related, but infrared sensors on the satellites can also detect large fires anywhere on earth. The infrared sensors do this by measuring differences in temperature. Computers help analysts evaluate the imagery. High temperature zones, or "hot spots," could represent fires.

Then it's up to the Mark Raminski and his Satellite Analysis Program team to cast their experienced eyes over the infrared satellite pictures.

"When the data comes in they run it through some computer algorithms. Those algorithms try and find where the fires are. But there are problems. It's not always as straightforward as we'd like it to be. So sometimes the algorithms, they may not catch all the fires. Sometimes it'll pick out things that really aren't fire. It's just hot ground that the algorithm thinks is a fire. Our job is basically quality control," Mr. Raminski said.

As the satellite information is displayed on computer screens, each pixel, or dot of the image represents a square kilometer in the target area. Since the polar orbiting satellites and geostationary satellites take infrared pictures at different times, the images can be put together as short animated videos that can better illustrate for Mr. Raminski and his staff where fires are burning and their movement through the forests.

Donna McNamara is with the National Environment Satellite Data and Information Service, a private service that works with NOAA to improve the system's accuracy. Ms. McNamara said this data is especially helpful in developing strategies for fighting multiple wildfires over wide areas of the United States.

"We can't help the firefighter battling a fire right out in front of him. He certainly knows more about that then we do, but we can help his managers know that, 'Gee maybe there's a fire starting a few miles away. And maybe we should pull some resources off from that team and have them start to attack another fire so they don't get surprised in another place.' Or, 'that resource is dedicated to say Northern Colorado, maybe it should be diverted to Arizona, because the Arizona fire is getting to be a more serious issue.'"

David Bunnell is a program manager with the U.S. Forest Service, based at the National Interagency Fire Center in Boise, Idaho. For workers on the ground, he said, the NOAA satellite information isn't as helpful as it could be, because they can't receive it in real-time, just yet. But he said it can be very helpful in monitoring the effects of the rainless lightning storms that often spark wildfires this time of year.

"In a lightning situation that is prevalent across the West, particularly from mid-summer on, the detection of those fires there are so many fires and the detection reports become so confusing. Many times, those detection reports can be sorted out during the next 24 hour period with satellite imagery from NOAA and other sources," Mr. Bunnell said.

Mr. Bunell said that with time, NOAA's information will become more useful to the Forest Service as real-time access becomes available and satellite information becomes more precise. He adds that military satellites can already see hot spots in increments smaller than a square kilometer. For now, Mr. Bunell relied on his most important assets, which are human eyes, and portable infrared cameras.

John Newman worked in the U.S. Forest Service for 30 years before starting his own infrared mapping company, which now does contract work with the Forest Service. He can cite many examples of how portable infrared cameras have been critical tools for firefighters. His favorite story involves a 1994 fire in Southern California that he helped to battle.

"We were able to get an infrared helicopter in. Instead of sending people in, we just monitored that line. What we found out was, the thing went out on its own with just a little help from some bucket-drops from helicopters. We actually did a cost analysis afterwards and discovered we saved over a million dollars by not sending people in. And [there is] no telling how many injuries we would have had, if we had sent those folks in there. So it was a real blatant example of the power of infrared intelligence that saved us from having to do an enormous amount of expensive work," Mr. Newman said.

Mr. Newman added that portable infrared cameras are quite helpful in seeing through clouds of smoke and spotting areas that might re-ignite after being extinguished. Sometimes smoldering logs or stump holes can remain hot enough to catch fire again later, even though they are not sending up any visible smoke.

Even as the power of fire-detection tools increases, forest fires are becoming more numerous and difficult to fight. Mr. Newman and Mr. Bunell both point to a reduction in prescribed burning in the United States as a cause for the record number and severity of forest fires this season.

A buildup of smaller plants and accumulated dead wood on the forest floor, can act as fuel for wildfires, and can make some areas more susceptible to large burns. In the past, the Forest Service routinely set controlled fires to burn this fuel off. But the policy has become controversial in recent years, especially after several prescribed fires got out of control and damaged private property.

Many forest experts are still convinced, however, that prescribed burns, managed correctly, are a sound way to reduce the threat of more destructive fires. Infrared mapper John Newman believes that technology could be developed to pinpoint where fuel buildup is most abundant and how it might affect a fire.

"One of the tools that has eluded us for several decades is a very useable model for modeling fuel behavior. That would help, not only on these wildland fires as to where they're going to go, but also how to better predict how to use prescribed fire. It might surprise you that a lot of times we don't where fires are at. We don't know how far they've moved in a day. We don't know what their pattern in certain fuels are at certain times, because we don't have real-time intelligence on those fires. If we can acquire that kind of intelligence, it will enable us to build better models that, in fact, should be very accurate models," Mr. Newman said.

While fuel behavior models might still be years away, important technological improvements in forest-fire control are already at hand. NOAA is upgrading and improving computers at its Maryland headquarters son the organization and fire services can make better use of satellite information. And officials in NOAA's fire detection program also say they expect the next generation of earth orbiting satellites will have improved imaging and fire detection capabilities.

To learn more about NOAA's international fire detection program, you can visit the agency's Internet site at www.noaa.gov

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