Continuity Vegetation Indices
Landsat 8, the most recently launched satellite of the series, promises to maintain the continuity of Landsat 7. However, in addition to subtle differences in sensor characteristics and vegetation index (VI) generation algorithms, VIs respond differently to the seasonality of the various types of vegetation cover. The purpose of this study was to elucidate the effects of these variations on VIs between Operational Land Imager (OLI) and Enhanced Thematic Mapper Plus (ETM+). Ground spectral data for vegetation were used to simulate the Landsat at-senor broadband reflectance, with consideration of sensor band-pass differences. Three band-geometric VIs (Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI), Enhanced Vegetation Index (EVI)) and two band-transformation VIs (Vegetation Index based on the Universal Pattern Decomposition method (VIUPD), Tasseled Cap Transformation Greenness (TCG)) were tested to evaluate the performance of various VI generation algorithms in relation to multi-sensor continuity. Six vegetation types were included to evaluate the continuity in different vegetation types. Four pairs of data during four seasons were selected to evaluate continuity with respect to seasonal variation. The simulated data showed that OLI largely inherits the band-pass characteristics of ETM+. Overall, the continuity of band-transformation derived VIs was higher than band-geometry derived VIs. VI continuity was higher in the three forest types and the shrubs in the relatively rapid growth periods of summer and autumn, but lower for the other two non-forest types (grassland and crops) during the same periods.
Authors: Xiaojun She, Lifu Zhang, Yi Cen, Changping Huang, and Muhammad Hasan Ali Baig
Keywords: hyperspectral; vegetation index; continuity; Landsat 7 ETM+; Landsat 8 OLI; Time series
Spectral Evolution is a leading manufacturer of field-portable UV-Vis-NIR remote sensing spectroradiometers and spectrometers for applications including geological remote sensing, ground-truthing, spectral remote sensing, environmental and climate research, crop and soil research, vegetative studies, forestry and canopy studies, radiometric calibration transfer, upwelling and downwelling measurement and more. Our UV-Vis-NIR spectrometers and spectroradiometers provide the best combination of high resolution and high sensitivity resulting in the most precise field portable instruments available on the market.
Spectral Evolution UV-Vis-NIR spectroradiometers provide:
- Fast, full-spectrum UV-Vis-NIR measurements – 350-2500 nm with just one scan
- Superior reliability in the field with 100% diode array optics with no moving parts
- Wireless Bluetooth® Connection
- Lithium-ion rechargeable batteries for field use
- Lightweight and rugged
- Rugged handheld tablet for field use running DARWin™ LT on Windows 10 with digital camera, and GPS
- Field switchable optics for varying target sizes and measurement modes
All Spectral Evolution UV-Vis-NIR spectroradiometers include our exclusive DARWin™ SP Data Acquisition and Analysis software for one-touch, full range spectroscopic analysis of samples. DARWin™ SP automatically saves data as ASCII files for use with 3rd party software without post-processing.