Click on the image to view a full-size version.
This image shows an estimate of cryptobiotic (microbiotic) soil coverage for an area in Arches National Park. In order to derive this map of the distribution and abundance of cryptobiotic soils, AVIRIS remote sensing data were compared to laboratory reference spectra of cryptobiotic soil samples. This image covers an approximately 10.5 km by 17.5km area of Arches National Park from the Colorado river in the south, Wolfe Ranch and Delicate Arch near the center, and Fiery Furnace and the campground area to the north.
This image was derived from AVIRIS data collected in 1992 and processed using the USGS Tricorder algorithm. AVIRIS is an imaging spectrometer remote sensing instrument. This instrument, flown on an ER-2 aircraft at 65,000 feet altitude, measures reflectance in visible to near infrared wavelengths in 224 contiguous channels (0.4 to 2.5 microns). Pixels are spaced 17 m apart.
Representative spectra of cryptobiotic soils, vegetation and soil background (sand, rock or soil) measured in the laboratory were combined mathematically in various mixtures. Remotely sensed spectra acquired by AVIRIS were then compared to the synthetic mixtures and the closest match determined for each pixel in the image. These data were field checked in 1994. Field checking showed that in some area black lichen on the sandstone had similar reflectance characteristics as the cryptobiotic soils. Thus, this image presents the distribution of "cryptobiotic soils AND black lichens."
Additional AVIRIS data were acquired in 1995. These new data cover all of Arches National Park and a majority of Canyonlands National Park. Preliminary mapping of this new data for mineralogy with the "tricorder" algorithm has been completed. Vegetation and cryptobiotic soils maps are currently being processed. Field verification is scheduled for fall of 1997. Updates on this project and other USGS projects involving imaging spectroscopy in National Parks and other areas can be obtained at http://speclab.cr.usgs.gov.