COLLEGE PARK, Md. – In January, ESSIC’s Wilfrid Schroeder processed the first satellite images of fire produced as a part of NASA’s Suomi National Polar-orbiting Partnership (NPP) and Earth Observing System (EOS).
The images were acquired by the Visible Infrared Imaging Radiometer Suite (VIIRS), an instrument attached to the NPP spacecraft launched in October 2011.
The VIIRS is one of five key instruments on the spacecraft that measure atmospheric and sea surface temperatures, humidity sounding, land and ocean biological productivity and cloud and aerosol properties that can then be distributed to meteorology and climate change researchers and scientists around the world.
The VIIRS observes thermal infrared energy, essentially detecting fires and then taking satellite images. The instrument first successfully detected fires on January 19, 2012, and produced two that Schroeder then processed and NASA published.
These images are the tip of the iceberg for Schroeder’s work on VIIRS fire algorithm development and validation activities.
“This is one project out of a bigger project in which we are generating data, so basically the idea is to produce a global climate data set on fire activity that uses a combination of satellites,” Schroeder said.
Schroeder is part of a team for the NPP that is responsible for developing the fire component of the mission, which includes the use of the VIIRS instrument on the satellite.
One of the images he processed is of a smoky fire burning in the mountains east of San Diego, California. The other shows widespread agricultural burning in South Sudan, East Africa. They are processed to include visualization of the features that Schroeder and his team are trying to highlight, like smoke coming from the image.
“For the regular user to understand what’s going on we make it so people can look and relate that to real life imagery like a camera picture,” said Schroeder.
NASA designed the NPP to produce weather related data that can be used for long term climate predictions, Schroeder said, and fire is one of the records that it keeps.
The data will be used by many different organizations globally for air quality monitoring, modeling and programs. The main user in the U.S. will be the United States Forest Service.
“They rely on this data not only to monitor and keep control of the situation, but over time, once we start collecting enough data, they will also use the data to manage national parks, doing fuel control, fuel management and crew management,” Schroeder said.
Schroeder and his team have been working through a validation process out in the field, coordinating controlled fires over a 540 hector area near San Jose, Calif.
The scientists coordinate the timing of these fires to within minutes of the NPP satellite passing overhead. Then, using a NASA aircraft, they fly over the fire while the satellite is passing to collect data from the air as well.
As a result, they are able to collect data from the ground where the fire is burning, the air as the aircraft passes over the fire, and 800 km above the ground from the satellite.
The coordination for this process has to be almost flawless: the images and data collected from the aircraft must be taken with fifteen minutes of the images and data collected by the satellite for them to be useful for validation purposes.
“We try our best to nail it down to no more than a couple minutes,” said Schroeder. “These guys, NASA, the forest service pilots, they do a great job; we usually get it down to no more than two minutes, so that’s pretty impressive.”
Coordinating the aircraft and the satellite together that perfectly isn’t easy.
“Once those flames start rolling it’s mayhem…coordinating ground, ignition, Air Force teams, it can always be challenging,” said Schroeder. “There’s always a risk of cloud coverage; the satellite has to have a clear view of the surface. There’s a whole lot of things that can go wrong.”
The Forest Service controls the fires from the ground, keeping them from passing outside of any given perimeter, and keeps them burning for six to nine hours. After the fires are put out, the data collected from the satellite can be validated by the data collected from the ground and from the aircraft.
While Schroeder and his team don’t perform these field tests often (one time can easily cost $20,000), the results are useful in the long term.
“Once you collect data, you will start to see patterns, like what area will burn during what part of the year; then you can anticipate the action,” Schroder said. “For example, you could see that, say, Florida burns in January, so you could assign people to that area and also resources to respond to that event almost immediately.”
According to Schroeder and his research, the United States has seen a recent increase in forest fires, with many scientists pointing to global warming as the cause.
“You can take different views of the problem. Some of the data records we have aren’t long enough to point to cause and consequence, but the modeling community in particular does have longer data sets we can rely on,” Schroeder said. “Of course you think hotter and warmer you think more fires, so it’s a natural conclusion to draw from them.”
Schroeder and his team are working hard to perfect the images they produce. Future VIIRS images will be significantly more detailed, actually showing the fires, where they are and what is actually burning.
Other U.S. organizations will use the VIIRS data as well, like the U.S. Naval Research Laboratory in Monterey, Calif., which will use the data to predict air quality and visibility before pilots take flight for international operations.
Schroeder plans on publishing another article for NASA Earth Observatory as a continuing part of the NPP program.
“Over the next several weeks we will be doing calibration and validation of the product,” Schroeder said. “So before the public gets to see the product we will have the quality check done.”