Photochemical reflectance Index

The Photochemical reflectance index or PRI is a reflectance measurement that is sensitive to changes in carotenoid pigments (e.g. xanthophyll pigments) in live foliage. Carotenoid pigments are indicative of photosynthetic light use efficiency, or the rate of carbon dioxide uptake by foliage per unit energy absorbed. As such, it is used in studies of vegetation productivity and stress. Applications include vegetation health in evergreen shrublands, forests, and agricultural crops prior to senescence. PRI is defined by the following equation:

$PRI=\frac{(p531-p570)}{(p531+p570)}$ ^[1]

Additional recommended knowledge

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Some authors use

$PRI=\frac{(p570-p531)}{(p570+p531)}$ ^[2]

p531

p750

The values range from -1 to 1.

Sources

[1] ENVI Users Guide

[2] Gamon, J.A., Penuelas, J. and Field, C.B. (1992). A narrow-waveband spectral index that tracks diurnal changes in photosynthetic efficiency. Remote Sensing of environment, 41, 35-44.

[3] Drolet, G.G. Heummrich, K.F. Hall, F.G., Middleton, E.M., Black, T.A., Barr, A.G. and Margolis, H.A. (2005). A MODIS-derived photochemical reflectance index to detect inter-annual variations in the photosynthetic light-use efficiency of a boreal deciduous forest. Remote Sensing of environment, 98, 212-224.

Category: Biophysics