Fire Towers in Space

By ROBERT LEE HOTZ

July 16, 1998 12 AM PT

TIMES SCIENCE WRITER

Oceanographer Gene Carl Feldman was in a planning meeting at the Goddard Space Flight Center in Maryland when firefighters in Florida unexpectedly telephoned. He could barely hear their question over the hoarse shouts, ringing phones and confusion at the other end of the line.

After battling flames, smoke and infernal heat for two weeks, they were desperate for a better view of the wildfires along a 125-mile corridor from Jacksonville to Cocoa Beach. As a last resort, they called Feldman, who manages data gathered for NASA by a commercial ocean surveillance satellite.

Even as they spoke, the satellite’s wide-angle sensor--programmed to take color images every day of plankton blooms, red tides, migrating schools of fish and other sea features--was already scanning the Florida coastline automatically.

Within 15 minutes, Feldman had the satellite image on his computer screen. He swore in amazement. “The whole east coast of Florida was one line of fires, blanketed in this pall of smoke,” he said.

Within an hour, the satellite image had been transmitted electronically to the emergency management center in Brevard County, where the firefighters for the first time could see the true scope of what they were up against.

Even in a normal year, nearly 175 million acres of forest and grasslands burn worldwide. But recent major fires in Mexico, Brazil and Indonesia have raised the problem of uncontrolled fires to a level that transcends the boundaries of traditional firefighting.

In response, hard-pressed emergency managers like those in Florida, who at any one moment were trying to track up to 50 blazes earlier this month, have started to draft satellites into service in their war against wildfires.

Designed originally to monitor seasonal environmental conditions, track the daily weather or monitor ocean conditions, these sensors are also giving emergency planners an unexpected vantage point on large fires.

Often scanning the entire globe every 24 hours, the satellites are able to watch a world of fire, from out-of-control agricultural fires in Indonesia and Central America to wildfires in densely settled Florida or across the trackless Yukon.

Scientists have a keen interest in the smoke particles arising from large fires like those still smoldering in Mexico, because smoke contributes to overall global pollution levels and affects the quality of the air people breathe. Clouds containing smoke particles are also thought to reflect absorb and solar energy in different ways than clouds formed from natural particles like dust or sea salt.

The use of satellites as fire spotters is so new that researchers are still working to understand how the various kinds of images can be most useful.

“More and more people are . . . actually looking at the satellite imagery to see how the fires are doing,” said fire expert Rick Ochoa at the National Interagency Fire Center in Boise, Idaho, which coordinates the U.S. response to major wildfires.

“A lot of times, I will see something in the satellite thermal imagery [which reveals differences in ground temperature] that suggests a wildfire, and I then will look at the visible satellite imagery for smoke plumes,” Ochoa said. “If I see a thermal image coming out of a satellite looking at Yosemite or Gila National Forest in western New Mexico, I know we have a big fire and I can get our people ready.”

No single satellite, however, offers firefighters a complete picture of a wildfire.

Each sensor measures the effects of a large fire in a slightly different way, satellite managers at NASA and the National Oceanic and Atmospheric Administration explained. Each has its strengths and its shortcomings:

* Peering into the infrared, sensors aboard the GOES-8 weather satellite can spot the thermal bloom of large wildfires that encompass many square miles or that spark into life far from any human observers. Researchers compare different infrared wavelengths to tell the difference between territory that looks warm because the sun heated it and hot spots caused by lava flows or brush fires. In the past month, the GOES sensors have detected a number of large wildfires near the Arctic Circle.

* Attuned to tiny particles in the atmosphere, a NASA sensor called the Total Ozone Mapping Spectrometer can detect the amount of smoke in the atmosphere every day, anywhere in the world. Earlier this year, the sensor tracked the huge smoke plumes from fires in Mexico extending as much as two miles up into the atmosphere as they drifted across California, Texas, Florida and Wisconsin and north into Canada.

* Calibrated for the visible and near-infrared spectrum, the wide-angle SeaWiFS sensor aboard the OrbView-2 satellite, operated by the Orbital Imaging Corp., can produce sharp images of fire fronts too large to be encompassed from the ground. Feldman used it to help the Florida firefighters. During the fires that raged in Indonesia earlier this year, researchers used it to monitor smoke plumes that enveloped much of the South Pacific.

Some orbital sensors can penetrate the cloud cover that on occasion may mask a serious fire.

Earlier this week, for example, several satellites were unable to monitor major fires burning in the Canadian province of Quebec near James Bay and Hudson Bay due to clouds. Even so, sensitive infrared radiometers aboard two NOAA environmental satellites were able to detect the heat signature of the flames and track the plume of smoke drifting southeast toward the United States.

And the view from the fire tower of space is about to get even better. Two commercial Earth-observation satellites, with sensors that should vastly expand the ability to monitor wildfires from orbit, are being readied for launch in 1999 and in 2000 by the Orbital Space Systems Group in Germantown, Md.

In the meantime, Jay R. Herman at NASA’s Goddard Center, who handles much of the data from the ozone spectrometer sensor, said he too is starting to get telephone calls from curious forest rangers and firefighters.

They want to know what the sensor, which offers a view of Earth through the ultraviolet spectrum, can add to the understanding of a wildfire.

Unlike other satellite sensors that rely on visible wavelengths, the ozone spectrometer sensor can unmistakably sort clouds from smoke by comparing different wavelengths of ultraviolet light, Herman said.

“With TOMS, the smoke signal just pops up,” Herman said. “If you look at a global image from TOMS, you can always know whether you are looking at smoke, dust or clouds.”

Eventually, experts hope to combine satellite data with information gathered by aircraft and by researchers at the fire front on the ground to better understand how fires around the world affect the health of the atmosphere or contribute to potential climate change.

“The important thing now is that the satellite systems have evolved to the point where we can do this kind of thing in a quick emergency situation,” said Feldman at Goddard. “Until recently, this kind of data was only available for research scientists.”

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

A World of Fire

Emergency crews are looking from fire towers in space to better monitor large wildfires. Satellite sensors can detect the heat signature of flames and the plumes of smoke from larger fires around the world.

Privately owned by Orbital Imaging Corp., which sells data to NASA.

In low Earth orbit.

Contains SeaWiFS sensor that takes color images of the globe.

Fire Sites on the Web:

The Operational Significant Event Imagery (OSEI) Homepage:

https://www.osei.noaa.gov/

National Interagency Fire Center:

https://www.nifc.gov/news/index.html

Special satellite coverage of Florida fires:

https://www.goes.noaa.gov/floridafires.html

Special satellite coverage of Mexico fires:

https://www.goes.noaa.gov/mexicofires.html