Back-to-School Burn: The Science of Wildfires
Back-to-School Burn: The Science of Wildfires
23 August 2016
published by http://www.jpl.nasa.gov
USA / Global You didnt need to check social media, read the newspaper or watch the local news to know that California wildfires were making headlines this summer. Simply looking up at a smoke-filled sky was enough for millions of people in all parts of the state to know there was a fire nearby.
Fueled by high temperatures, low humidity, high winds and five years of vegetation-drying drought, more than 4,800 fires have engulfed 275,000-plus acres across California already this year. And the traditional fire season the time of year when fires are more likely to start, spread and consume resources has only just begun.
With wildfires starting earlier in the year and continuing to ignite throughout all seasons, fire season is now a year-round affair not just in California, but also around the world. In fact, the U.S. Forest Service found that fire seasons have grown longer in 25 percent of Earth’s vegetation-covered areas.
For NASA’s Jet Propulsion Laboratory, which is located in Southern California, the fires cropping up near and far are a constant reminder that its efforts to study wildfires around the world from space, the air and on the ground are as important as ever.
JPL uses a suite of Earth satellites and airborne instruments to help better understand fires and aide in fire management and mitigation. By looking at multiple images and types of data from these instruments, scientists compare what a region looked like before, during and after a fire, as well as how long the area takes to recover.
While the fire is burning, scientists watch its behavior from an aerial perspective to get a big-picture view of the fire itself and the air pollution it is generating in the form of smoke filled with carbon monoxide and carbon dioxide.
Additionally, JPL is working with a startup in San Francisco called Quadra Pi R2E to develop FireSat, a global network of satellites designed to detect wildfires and alert firefighting crews faster. When completed in June 2018, the network’s array of more than 200 satellites will use infrared sensors to detect fires around the world much faster than is possible today. Working 24 hours a day, the satellites will be able to automatically detect fires as small as 35 to 50 feet wide within 15 minutes of when they begin. And within three minutes of a fire being detected, the FireSat network will notify emergency responders in the area.
Using these technologies, NASA scientists are gaining a broader understanding of fires and their impacts.
Why It’s Important
One of the ways we often hear wildfires classified is by how much area they have burned. Though this is certainly of some importance, of greater significance to fire scientists is the severity of the fire. Wildfires are classified as burning at different levels of severity: low, medium, and high. Severity is a function of intensity, or how hot the fire was, and its spread rate, or the speed at which it travels. A high-severity fire is going to do some real damage. (Severity is measured by the damage left after the fire, but can be estimated during a fire event by calculating spread rate and measuring flame height which indicates intensity.)
The impacts of wildfires range from the immediate and tangible to the delayed and less obvious. The potential for loss of life, property and natural areas is one of the first threats that wildfires pose. From a financial standpoint, fires can lead to a downturn in local economies due to loss of tourism and business, high costs related to infrastructure restoration, and impacts to federal and state budgets.
The release of greenhouse gases like carbon dioxide and carbon monoxide is also an important consideration when thinking about the impacts of wildfires. Using NASA satellite data, researchers at the University of California, Berkeley, determined that between 2001 and 2010, California wildfires emitted about 46 million tons of carbon, around five to seven percent of all carbon emitted by the state during that time period.
In California and the western United States, longer fire seasons are linked to changes in spring rains, vapor pressure and snowmelt all of which have been connected to climate change. Wildfires serve as a climate feedback loop, meaning certain effects of wildfires the release of CO2 and CO contribute to climate change, thereby enhancing the factors that contribute to longer and stronger fire seasons.
While this may seem like a grim outlook, its worth noting that California forests still act as carbon sinks natural environments that are capable of absorbing carbon dioxide from the atmosphere. In certain parts of the state, each hectare of redwood forest is able to store the annual greenhouse gas output of 500 Americans.
Studying and managing wildfires is important for maintaining resources, protecting people, properties and ecosystems, and reducing air pollution, which is why JPL, NASA and other agencies are continuing their study of these threats and developing technologies to better understand them.
Teach It
Have your students try their hands at solving some of the same fire-science problems that NASA scientists do with these two lessons that get students in grades 3 through 12 using NASA data, algebra and geometry to approximate burn areas, fire-spread rate and fire intensity:
Fired Up Over Math: Studying Wildfires from Space – In this activity, younger students use arithmetic, scale, and math tiles; middle school students employ rate and partial polygon area formulas; and high school students use Google Earth software embedded with recent NASA wildfire data to make inferences about fire severity.
Pixels on Fire In this technology-based lesson, students detect mock fires using mobile devices and study NASA data visualizations to determine when actual California wildfires started.
Explore More
NASA/JPL FireSat Press Release
SciJinks: Can Meteorologists Help Fight Wildfires?
Soberanes Fire: Image Captured by NASA’s Terra Spacecraft
Let’s Clear the Air: The Danger of Forest Fire Smoke to Firefighters
