From The Editor | June 14, 2023

Come On Baby Track My Wildfire

John Oncea

By John Oncea, Editor

Wildfires-istock_1198540877

The recent rash of wildfires burning in Canada has drawn attention to a problem that most experts agree is only going to get worse over the coming months and years. Many technologies are being used to help fight these wildfires, including infrared.

There are, according to the Canadian Interagency Forest Fire Centre, nearly 500 active wildfires in Canada, * of which 226 are deemed “out of control.” These fires make an “unprecedented” start to Canada’s wildfire season, one that the Canadian government said has “the potential for continued higher-than-normal fire activity across most of the country throughout 2023” due to ongoing drought and forecasts for warm temperatures.

“For weeks, the smoke from wildfires in different regions in Canada has been making its way South,” reports ABC News. “In May, air quality alerts were issued in Montana, Idaho, Colorado, and Arizona due to wildfires burning in Alberta. By May 31, smoke from wildfires burning on the other side of the country, in Nova Scotia, led to the first stretch of air quality alerts in the Northeast.”

“We are already seeing one of the worst wildfire seasons on record, and we must prepare for a long summer,” said The Honorable Steven Guilbeault, Minister of Environment and Climate Change. “The Government of Canada is stepping up to the request for assistance from Quebec and will immediately begin mobilizing Canadian Armed Forces, firefighting resources, and assistance with planning to support the wildfire response in the province.

“The threat of increased fires due to climate change is one of the many reasons our government is developing a robust National Adaptation Strategy with all levels of government and Indigenous groups, so we can be sure our communities are well prepared for the impacts of climate change.”

* As of June 13 at 3:30ish.

With the threat of “unprecedented” wildfires burning “out of control,” nearly every industry is hard at work looking for ways to help, including those in the photonics industry. Infrared is being looked to as a technology that can be used to study, detect, and track developing fires faster and provide a greater chance of keeping the damage to a minimum through timely intervention.

Inverse reports that researchers monitoring the smoke from the recent Canadian wildfires using a combination of NASA laser instruments on the ground and a fleet of low-Earth satellites were surprised to learn that, “Just like rock layers record Earth’s geological history, layers of smoke in the giant plume record a much more ephemeral history of this year’s Canadian wildfires.

“The layer of smoke closest to the ground towers two miles into the atmosphere before it gives way to relatively clear skies. About four miles up, a thinner layer of smoke hovers above it. And about 7.5 miles above the ground, a very faint layer is all that’s left of fires in Alberta, in western Canada, in May.”

This discovery was made in part due “to two networks of lidar instruments, which use lasers to measure the distance to objects or surfaces, like cloud layers. The ground-based Micro-Pulse Lidar Network (MPLNET) and the satellite CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) are both helping measure the height of different layers of smoke.”

“There are different histories to each one of those layers that would be interesting to untangle,” said Michael Fromm, an atmospheric scientist at the U.S. Naval Research Laboratory, after seeing the MPLNET data. “The layer lurking at 12 kilometers is a month old and can be traced back to intense fires in Alberta on May 5.”

This knowledge might not help prevent or extinguish wildfires, but it could help provide warning to populations that would be adversely affected by the smoke from wildfires such as what happened in the Northeast this past May. That said, NASA is working with infrared technology to help the agencies fighting wildfires make better decisions.

The NASA Earth Science Applied Sciences Program reviewed the current state of NASA infrared imaging in how it is used to track wildfires and found, “For every major wildfire incident, precise information on fire perimeter size and rate of progression is critical for ‘incident personnel on where to concentrate their resources and assist in informing local people and media on the fire status,’ that according to the National Interagency Fire Center. Several mapping methods are used to determine fire size and spread, including the use of GPS by walking/driving, image interpretation, and infrared flights.”

Wildfire decision makers rely heavily on infrared data to gather information on the progression and perimeters of fires. This data is collected through two main methods: aerial sensing and satellite imagery.

Aerial sensing involves mounting infrared sensors on planes, such as NASA's MODIS/ASTER (MASTER) Airborne Simulator. Since large wildfires cannot be captured in one flyover, MASTER is flown over the fire multiple times in parallel lines. The resulting images are then stitched together to form a complete infrared image of the fire.

However, this composite image is not easily interpretable, so agencies like the U.S. Forest Service employ infrared imaging interpreters, also known as IRINS, to create geospatial information. These interpreters play a crucial role in helping decision makers and wildland firefighters strategize and allocate firefighting resources.

IRINS “will typically create two, easy-to-read, categories which group heat detections from airborne sensors: intense heat and “scattered heat. Intense heat is typically associated with flaming fronts, meaning areas of the highest fire intensity and activity. Scattered heat is typically used for areas with dispersed pockets of fire and regions with mixed fuel types.”

Areas with scattered heat indicate that the fire is likely to burn with less intensity compared to regions with intense heat. While there is no specific numerical value to differentiate between the two categories, experts who interpret infrared images typically identify areas with the most concentrated and brightest infrared detections as intense heat regions. On the other hand, scattered heat regions are characterized by lower and more dispersed readings.

Satellite imagery also serves a critical role in infrared imaging and detection. Some examples of instruments and missions include the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua and Terra satellites; the Geostationary Operational Environmental Satellites (GOES); and the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard NASA and satellites operated by the National Oceanographic and Atmospheric Administration (NOAA).

These tools provide near-real-time detection of wildfires and are useful for managing such incidents. The 375m VIIRS active fire product and 1 km MODIS active fire product have different spatial resolutions, but both are effective in detecting thermal activity, identifying potential wildfires, determining fire type, and measuring fire radiative power values.

The fire radiative power is a crucial data attribute in satellite fire products. It enables us to estimate the intensity of heat generated by a wildfire for single active fire detection, as well as a group of detections. This numerical data creates a gradient of values that serves as a visual indicator of fire intensity concentrations. Firefighters can use this information to anticipate possible expansion and determine where to focus their efforts.

NASA plays a crucial role in tracking and imaging active fires using both aerial and satellite platforms. In light of the ongoing prevalence of wildfire incidents in the western, central, and southern regions of the United States, firefighters and wildfire decision makers need to have access to reliable fire mapping products that are easy to interpret. By providing strong visual aids generated from data, incident management can make informed decisions quickly and efficiently. The fire products and science developed by NASA play a significant role in protecting lives, property, and landscapes.