SPACEPHOTOS

Airborne images of the Willow fire in Southern California's San Bernardino County, taken September 1 from a NASA ER-2 airplane, show the blaze in wavelengths that are not visible to the naked eye and would vastly improve firefighters' ability to contain them. Whereas the human eye can only see in the visible portion of the light spectrum, from 400 nanometers to 700 nanometers, NASA's Airborne Visible/Infrared Imaging Spectrometer, known as AVIRIS, measures the full spectrum of light from 400 nanometers to 2,500 nanometers. (A nanometer is one-billionth of a meter.) The color portion of the first set of images, beginning at the left, shows the Willow fire as it was seen from an aircraft on September 1. Vegetation is dark green and smoke can be seen rising from the fire. To the left of the color image is the first infrared image taken at a wavelength of 500 nanometers. The light is diffused by smoke particles and vegetation appears dark due to the absorption of chlorophyll molecules. In the next spectral image, taken at 1,000 nanometers, less of the light is scattered by the smoke and the surface near the fire is seen more clearly. At this wavelength of light, healthy vegetation appears bright because of the light scattering of leaves, while scorched vegetation appears dark. At the still longer wavelength of 1,500 nanometers, the smoke is nearly transparent. At this wavelength, AVIRIS began to clearly measure the actual light coming from the burning fire. At 2,000 nanometers, only light from the burning fires can be seen. In this image the major fires and many small hotspots can be seen. In the future, AVIRIS will continue to be used to gather valuable information on forest fire risk in both wilderness and urban areas. Currently, important research is being pursued by Drs. Dar Roberts of the University of California, Santa Barbara, Susan Ustin of the University of California, Davis and John Gamon of California State University, Los Angeles, as well as many others. AVIRIS was designed, built and is operated by the Jet Propulsion Laboratory for NASA's Earth Science Enterprise. With full spectral coverage, AVIRIS data are used to carry out a range of research activities and applications covering ecology, geology, coastal and inland water studies, snow and ice studies, wild fires, environmental contamination and urban studies. Data collection is made possible by NASA's ER-2 aircraft, which is housed at the Dryden Research Center at Edwards Air Force Base, CA. JPL is a division of the California Institute of Technology, Pasadena, CA.