Satellite Data Helps to Combat Western Fires
NASA Satellite Data Used Operationally to Help Combat Fires in the West Lynn Chandler
David W. Tippets
September 12, 2000
There was no Labor Day holiday for firefighters battling dozens of blazes that have consumed hundreds of thousands of acres across Montana and Idaho. But fire officials did get some assistance from an unexpected source as scientists from NASA, NOAA, the USDA Forest Service and the University of Virginia teamed up to provide them with new observations of the fires from NASA's Terra satellite. This marked the first time data from the recently-launched spacecraft were used operationally in a crisis situation. On Aug. 30 and 31, President Clinton declared parts of both Montana and Idaho disaster areas due to widespread wildfires. On Sept. 1, scientists from NASA's Goddard Space Flight Center (Greenbelt, Md.) and NOAA began providing Forest Service officials with daily images acquired over those states by Terra's Moderate-resolution Imaging Spectroradiometer (MODIS) instrument. According to Wei Min Hao, project leader of the Fire Sciences Laboratory for the Forest Service's Rocky Mountain Research Station, MODIS data helped firefighters pinpoint where the fires were burning, where there were still-smoldering burn scars, and where smoke from the blazes was spreading. "On days when there is heavy smoke, observers in reconnaissance planes are unable to see the fire through the smoke," says Hao. "So we must rely on thermal infrared sensors and satellite imagery. During this historic fire season there are so many fires over such a large area and we have such limited resources, without the satellite images we could not see the real extent of the fires and know where to allocate firefighting resources." According to Hao, satellite images from MODIS and NOAA's Advanced Very High Resolution Radiometer (AVHRR) provided a quick overview of where the fires were most active on the previous day. This information helped the firefighters plan each day's strategy and decide how to allocate resources for monitoring and if necessary battling the blazes. Terra Project Scientist Yoram Kaufman explains that the MODIS sensor observes the fire region in 36 different wavelengths of the spectrum, ranging from visible to thermal infrared light, so it has the capacity to see through the smoke in the atmosphere to detect hot flames on the surface. MODIS also has new channels that enable scientists to distinguish flaming fires from still-smoldering burn scars. "MODIS can detect smoke at a resolution four times greater than AVHRR (NOAA's heritage instrument for MODIS), and MODIS uses several spectral channels in the solar spectrum so it can see the smoke more clearly," says Kaufman. "MODIS can also see burn scars at resolutions as high as 250 meters." "Ultimately, this is good for the people at the fire fighting command center," adds Hao. "The MODIS data helps them monitor smoke dispersion, which is a critical issue for the health of those living in the area." According to Chris Justice, MODIS Land Discipline Group Leader and research professor at the University of Virginia, MODIS will also make important new contributions to monitoring fires on a global scale by helping scientists better gauge how much gas and aerosol particles they emit every year. In the U.S. alone, more than 6 million acres have burned this year, which is 2.5 times the annual average. Preliminary calculations by Stefania Korontzi (UVa), a member of the MODIS fire group, estimate that the fires this summer in Montana, Idaho, Nevada, and Utah have released approximately 76 teragrams (76 million metric tons) of carbon dioxide. Annual estimates from the USFWS for the entire United States, averaged from 1988-96, range from 33 to 189 teragrams (33 to 189 million metric tons) of carbon dioxide that are released by wildfires each year. "These preliminary calculations show that the emissions from these wildfires are significant," says Justice. "The MODIS fire group will be developing better estimates of emissions in the coming months, using MODIS data to provide estimates of the total area burned. The improved spatial resolution and spectral band selection of MODIS allows improved mapping of burn scars." One advantage Terra had in observing the fires is that it orbits over the area in the morning, Hao said. MODIS tends to get more shots of the fires than NOAA's AVHRR instrument, which flies over in the afternoon because there is typically less cloud cover in the morning. Using the two satellites in tandem gives firefighters the best possible chance of getting unobstructed views of the fires. "It is very exciting that new satellite technology, as manifest in the MODIS instrument on Terra, can be used not only to do new Earth system science, but it can also be used to help monitor wildfires, save lives and property, and monitor air quality," says Kaufman. Kaufman says this is the first time Terra data have been made available operationally. He says the MODIS Team, based at Goddard Space Flight Center, is making the data available on an experimental basis. "We are testing our ability to deliver the data operationally within 24 hours of acquisition," he explains. "We hope to be able to deliver the data operationally in the future using MODIS' direct broadcast capabilities." Any agency or organization that has a proper receiving station can freely receive direct broadcast MODIS data every time the satellite flies overhead. Moreover, a copy of the MODIS sensor will also launch in December 2000 aboard Aqua, Terra's sister satellite. Once both sensors are in orbit, MODIS will see any given place on the Earth's surface as often as four times per day. For more information: NASA Demonstrates New Technology for Monitoring Fires from SpaceMore Moderate Resolution Imaging Spectroradiometer (MODIS) Images of Fire: Smoke in the Bitterroot Mountains |
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