Average reflectance for an area of grassland invaded by the invasive plant species leafy spurge (Euphorbia esula L.). The area measured was approximately 15 meters in diameter. The leafy spurge cover was approximately 60% (estimated visually). The remainder of the rocky soil was covered by mixed native grass and litter. The spurge plants were approximately 0.4 m in height. The leafy spurge plants in the area were in various stages of senescence. Leaves and stems were predominantly orange with some occasional red and green plants occurring. More green stems were present in this area (Site A) compared to sites B and C. The grass cover was dry, brown, and sensescent. The spectra were collected with the head of the spectrometer pointed approximately at nadir, approximately 1 meter above the ground surface, while the operator walked through the area recording spectra. This average spectrum was computed from 34 individual recorded spectra (each recorded spectrum was an average of 60 measurements). The spectra were measured on October 22, 1997. This area of leafy spurge is situated on a southwest facing slope in an area that had been grazed by cattle. The general location is a rural area on the northern edge of the city of Golden, Colorado (GPS coordinates are 39 degrees 47.062 minutes N latitude, 105 degrees 14.425 minutes W longitude; Datum = WGS84). The specific location (Site A) of the area from which this average spectrum was computed is 25 meter NW of the given GPS coordinates. Sky conditions during the measurement were hazy with some small cumulus clouds present by the end of the data collection. This is the same area measured for spectra Spurge-A1-Sep97, Spurge-A1-Jun98, and Spurge-A1-Jul98. Photos of the sample: None
X Units
cm⁻¹
Y Units
Absorbance
Data Points
2,126
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Attribution
USGS Spectral Library Version 7, U.S. Geological Survey