J.roemer. DWV1-0511c grbrn.a

Spectrum Details

Modality

NIR

Category

vegetation

Material Type

PLANT

Sample ID

Juncus roemerianus at DWV1-0511

Collection Locality

Northern Barataria Bay, approximately 58 km south-southeast of New Orleans, Louisiana

Spectral Purity

1a2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

Sample Description

This spectrum is the average reflectance of 7 field measurements (using an artificial light source) of green and brown leaves and stems of black needlerush (Juncus roemerianus). Measurements were made at locations close to the tips of the leaves, in order to incorporate both brown and green portions of the plants. The measurements were made on May 12, 2011. These spectra were collected using an ASD Field Spectrometer 3 (FS3) in reflectance mode, relative to a Spectralon reference panel. The contact probe attachement (an artificial light source with a restricted, 1 cm diameter, field of view) was used to measure the reflectance spectra of bundles of leaves and stems. Plant stems and leaves in the top 30 cm of the canopy were bunched together. The contact probe was pressed against the optically thick bundle and a spectrum was recorded. An average spectrum was computed from the recorded measurements. The average spectrum was converted to absolute reflectance by multiplying by the reflectance spectrum of the Spectralon reference panel. The first 50 channels (0.35 - 0.40 microns) in the spectral measurement show relatively high levels of noise. Project Background This site was measured as part of joint work between the USGS Denver Spectroscopy Laboratory and the Coastal Restoration Assessment Branch of the USGS National Wetlands Research Center, Baton Rouge. IMAGE_OF_SAMPLE:

X Units

cm⁻¹

Y Units

Absorbance

Data Points

2,126