Broadband and Narrowband Greenness Vegetation Indices

Broadband greenness measures the health of vegetation by comparing strong reflective properties in NIR wavelengths (700- 1300nm) with the strong absorption features in the red wavelengths. These vegetation indices include NDVI (Normalized Difference Vegetation Index), EVI (Enhanced Vegetation Index), and ARVI (Atmospherically Resistant Vegetation Index). NDVI normalizes green leaf scattering in the NIR and chlorophyll absorption in the red. EVI uses information in the blue wavelength to improve NDVI in areas of dense canopy by correcting background noise and atmospheric influence. ARVI is resistant to atmospheric influences.

Narrowband greenness measures the overall amount and quality of photosynthetic material in vegetation. The vegetation indices in this group use reflectance bands in the red and NIR to sample the red edge portion of the spectra. The red edge is the steep slope between 690nm and 740nm caused by the transition from chlorophyll absorption to NIR leaf scattering (increased reflectance). Indices include GRVI (Green Ratio Vegetation Index), Red/Green Ratio, Green NDVI (Green Normalized Difference Vegetation Index), and NDVI705 (Red Edge Normalized Vegetation Index). These indices incorporate red edge data with a leaf specular correction.

Spectral Evolution field portable spectroradiometers run DARWin SP Data Acquisition software with access to more than 19 vegetation indices through pop-up menus. Researchers can select those indices that will work best for the measurements they want to take and the vegetation characteristics they need to identify and monitor.

Spectral Evolution field spectroradiometers for remote sensing applications include:

  • SR-6500 ultra-high resolution field spectroradiometer for analyzing the finest spectral featuresuse with our Miniprobe and ILM-660 for soil analysis and mineral identification; use our unique leaf clip for vegetation studies. Available with a range of fiber mount Field of View lenses
  • NaturaSpec™ high resolution field portable spectroradiometer for in situ measurements with high resolution and sensitivity, use with our contact probe, Miniprobe, leaf clip and a range of fiber mount Field of View lenses
  • RS-8800 high resolution spectroradiometer controlled via iPhone, Android device or tablet, used with the Sensaprobe grip to provide real-time accurate measurements of scan angle, sun angle, distance from target and real-time target viewing
  • PSR+ full range (350-2500nm) high reslution/high sensitivity spectroradiometer with swappable direct attach lenses or fiber optic cable for use with FOV lenses, leaf clip, contact probe, diffuser and other accessories
  • RS-3500 remote sensing bundle with fiber optic cable connection for leaf clip, FOV lenses, contact probe and other accessoriues
  • PSR-1100F lightweight portable spectroradiometer with 320- 1100nm range

Field portable spectrtoradiometers and spectrometers can deliver the following advantages over lab methods:

  • Samples are more accurate as they are taken directly in the field or at the silo
  • Real-time results provide the ability to do spot testing
  • There’s no sample prep, no sample destruction, no shipment to a lab and waiting for results
  • You can track forage trends and plan your supplemental use
  • Test as weather and storage conditions change
  • Save scans as ASCII files for use with other chemometric and analysis programs
  • With a full range spectroradiometer, such as the PSR+ 3500, use EZ-ID sample identification software with its Custom Library Builder module to create a specific calibration library to suit your particular requirements