Fire Image Offers Lesson in Space-Based Observations
What can an instrument in space tell us about the fires tearing through southern California? This image of the Station fire, taken by JPL's Multi-angle Imaging SpectroRadiometer (MISR) on NASA's Terra satellite, shows an extremely large area and provides information about air quality as a result of the fire, which began on Aug. 26, 2009.
What this image tells us
The area covered by this image, taken on Sunday, Aug. 30, is 245 kilometers (152 miles) wide. Several pyrocumulus clouds, created by the Station fire, are visible above the smoke plumes. Smoke from the fire is seen covering the interior valleys along the south side of the San Gabriel Mountains (JPL is located here, but safe from the fire), and can be seen drifting for hundreds of kilometers to the east over the Mojave Desert.
Since data from the instrument takes a day to process, this image helps scientists study the smoke, dust and other particles that go into the atmosphere due to the fire. MISR also measures the altitude where the particles enter the atmosphere. In the case of this fire, the instrument detected smoke reaching more than 7 kilometers (almost 4.5 miles) above sea level, which is very high. This means that the smoke can be transported large distances downwind and affect air quality far away.
Comparing the views provided from space and the ground, JPL's Dave Diner, the instrument's principal investigator, explained, "I think it is interesting to compare the images of the fire and smoke taken from cameras on the ground to the image acquired from space. The satellite image shows just how extensively the smoke plumes extend (hundreds of kilometers), while the ground-based pictures show the human impact."
Remote sensing at work
NASA has a wide range of Earth-observing satellites equipped with high-powered imaging instruments and other detectors. These satellites and their instruments provide what is called "remote sensing," making observations of Earth from space.
As scientists try to understand impacts of events such as the Station fire on air quality, or to understand how the prevalence of wildfires might be affected by a warming climate, the ability to make accurate predictions depends on understanding how physical processes on Earth work. The large-scale context provided by satellites, and the ability to observe events even in very remote locations, gives a valuable database with which to test our computer models as well as to observe how Earth is changing.
The full image and caption for Station fire image is at http://photojournal.jpl.nasa.gov/catalog/PIA12190
For more information on how NASA helps monitor Earth, visit http://climate.nasa.gov/
To learn more about the Multi-angle Imaging SpectroRadiometer, go to http://www-misr.jpl.nasa.gov/mission/minst.html
To learn more about the Station fire, visit your favorite news Web site.