| Title | UNMIXING OF AVIRIS HYPERSPECTRAL DATA FROM DIXIE VALLEY, NEVADA |
|---|---|
| Authors | Glenn W. Johnson, Gregory D. Nash |
| Year | 1998 |
| Conference | Stanford Geothermal Workshop |
| Keywords | Dixie Valley, Nevada |
| Abstract | The high temperature hydrothermal convection system underlying northwestern Dixie Valley, Nevada, is probably responsible for the development of certain geobotanical anomalies in the area. A large ìdie-offí of Baileyís greasewood (Sarcobatus baileyi) has been observed over the last several months and appears to be related to activity that preceded the appearance of a new fumarole. AVIRIS (Advanced Visible and Infrared Imaging Spectrometer) airborne hyperspectral data was acquired for this area in May 1995, several months before the die-off was first recognized. Analysis of hyperspectral remote sensing data using polytopic vector analysis has resulted in the characterization of vegetal-spectral anomalies in the area of the die-off. Four spectral ìfingerprintsî were resolved and mapped. One of the four appear related to the S. baileyi die-off. Its spectrum closely matches spectra of healthy S. bailey. EM-1 was largely absent in the present area of the die-off at the time of the AVIRS image was collected. The fact that the analyzed AVIRIS image was taken months before the die-off was observed in the field suggests that spectral unmixing may prove an effective tool in anticipation of vegetative stress. |