2016_10_19_Meerdink_HyspIRI_Workshop.pdf (5.69 MB)
Spectral emissivity features of plants: Prospects for the Hyperspectral Thermal Emission Spectrometer (HyTES) sensor
Presented at the 2016 HyspIRI Workshop: hyspiri.jpl.nasa.gov/events/2016-hyspiri-science-and-applications-workshop
The
Thermal Infrared (TIR) spectrum has not been widely adopted for vegetation
studies due to the limited availability of TIR sensors, low signal to noise
ratios, and subtle features of plant spectra. However, recent improvements in TIR sensor design, atmospheric correction, and
temperature emissivity separation have begun to achieve the necessary data
quality for discerning TIR spectral features in plants. These technical developments make it possible to
re-examine the TIR emissivity characteristics of plants. The Hyperspectral Thermal Emission Spectrometer (HyTES) airborne sensor has 256 bands that measures radiance between
7.5 - 12 μm and can be used to retrieve spectral emissivity with high precision.
Here we evaluate TIR spectral variation between plant species at leaf and canopy
scale using HyTES imagery. HyTES imagery was acquired over Huntington Gardens in
Pasadena, California, US on 1/25/2016 with a spatial resolution of 2 m. Leaf samples were collected on 2/2/16 from a diversity
of trees species that had canopies larger than 10 m in diameter. Leaf spectra
were collected using a
Nicolet Model 6700 Interferometer Spectrometer fitted with a Labsphere gold
coated integrating sphere which measured emissivity from 2.5 – 15.4 µm. While
plant features are subtler and have lower reflectance in the TIR than the
visible shortwave infrared spectrum, plants showed considerable spectral
diversity at the leaf and canopy level using HyTES imagery. These analyses
support the first steps of using HyTES imagery for future remote sensing
vegetation studies.