NASA Takes Flight to Study California's Wildfire Burn Areas
While the agency's satellites image the wildfires from space, scientists are flying over burn areas, using smoke-penetrating technology to better understand the damage.
A NASA aircraft equipped with a powerful radar took to the skies
this month, beginning a science campaign to learn more about several wildfires that have scorched
vast areas of California. The flights are being used to identify structures
damaged in the fires while also mapping burn areas that may be at future risk
of landslides and debris flows.
They're part of the ongoing effort by NASA's Applied
Sciences Disaster Program in the Earth Sciences
Division, which utilizes NASA airborne and satellite instruments to generate maps and other
data products that partner agencies on the
ground can utilize to track fire hotspots, map the extent of the burn areas,
and even measure the height of smoke plumes that have drifted over California
and neighboring states.
Equipped with the Uninhabited
Air Vehicle Synthetic Aperture Radar (UAVSAR) instrument, the C-20A jet began flights from NASA's Armstrong Flight Research Center near Palmdale,
California, on Sept. 3. This first flight surveyed the LNU Lightning Complex
burn area northeast of San Francisco. A Sept. 9 flight focused on fires south
of Monterey in Central California.
A C-20A aircraft based out of NASA's Armstrong Flight Research Center flew used Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) and a short wavelength infrared imager to assess California fires on Sept. 3 and 10. The imager peers through wildfire smoke to examine the ground below, while UAVSAR enables scientists to get a close-up view of how these fires have altered the landscape. Attached to the bottom of the aircraft, the radar is flown repeatedly over an area to measure tiny changes in surface height with extreme accuracy. Image Credit: NASA
Several of the areas have been systematically imaged by
UAVSAR approximately every year beginning in 2009, with the two most recent
data collections being in 2018 and 2019 as part of larger earthquake-fault
monitoring studies. When images from those previous overflights are combined
with the new images, the science team can produce what are called damage proxy
maps to identify the areas most affected by the fires and plot the location of structures
that may have burned.
After vegetation is burned away, hillsides and valleys can
become susceptible to landslides and debris flows during seasonal rains, often
months later. By identifying the areas most at risk, scientists can better understand where such hazards may be greatest
when the much-needed rains begin in California later this fall.
The UAVSAR radar pod is mounted
to the bottom of the aircraft and is flown repeatedly over an area to measure tiny
changes (a few millimeters, or quarter inch) in surface height with extreme accuracy.
The smoke-penetrating instrument is also highly effective at mapping burn scars
because radar signals bounce off vegetation in a very different way than they
do off freshly burned ground.
What's more, UAVSAR airborne
flights over burn areas produce observations that are 10 times higher in
spatial resolution than satellites, and flights can be quickly arranged to
collect data over vulnerable areas identified in satellite images.
"UAVSAR has proven to be an
invaluable tool to detect tiny changes in the height of the land," said
Yunling Lou, UAVSAR project manager at JPL. "But this radar can also make
exquisite measurements of burn scars on any given day and provide daily repeated
measurements if needed, which complements mapping efforts by NASA satellites."
Accompanying the radar on the next set of UAVSAR wildfire
flights will be an infrared imager - an instrument that can see through dense
smoke and identify active fires - and a visible camera, which are both part of
the QUAKES-I (Quantifying Uncertainty and Kinematics of Earth Systems Imager)
imaging suite. Scientists will be able to harness the
data to generate detailed ground elevation maps in the fire burn areas.
"We want to use a
combination of radar, infrared, and visible imagery to understand where the
wildfire is currently active, to map the burn area, and to understand what areas
may have an elevated susceptibility of future landslides or debris flows,"
said Andrea Donnellan, a principal research scientist at JPL.
These mark the first mapping flights with UAVSAR to support
NASA's Disaster Program's data products as California continues to battle some
of its worst wildfire seasons on record. These data
products are prepared for agencies working on the ground in California,
including the California National Guard, California Department of Forestry and
Fire Protection (Cal Fire), Governor's Office of Emergency Services, California
Geological Survey, and Federal Emergency Management Agency.
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