Paper
17 December 1999 Vegetation change monitoring with spectral indices: the importance of view and sun angle standardized data
Willem J. D. van Leeuwen, Alfredo R. Huete, Trevor W. Laing, Kamel Didan
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Abstract
Remotely sensed reflectance data are often acquired at variable view and solar geometric configurations. Vegetation change monitoring with the NDVI (Normalized Difference Vegetation Index) is sensitive to the effects of solar and view angle geometry. However, by using a BRDF (Bidirectional Reflectance Distribution Function) model, the view and sun angle variability in the NDVI can be standardized. If multi- sun angle data are not available, a second method allows us to extrapolate (nadir) satellite observations to a standard sun angle by using predetermined linear regression relationships between sun angle and ground-based nadir NDVI values for a range of vegetation types. Both methods were applied to one month of daily, atmospherically corrected, multi-angle SeaWiFS (Sea viewing Wide Field-of-view Spectroradiometer) land reflectance data, with promising results. The difference in NDVI due to a sun angle change from 20 degrees to 70 degrees can be up to 50%. The NDVI values for very dense vegetated and bare soil surface areas are less affected by changes in solar zenith angles. This research shows that the sun and view angle effects on the widely used spectral indices could be standardized to improve the accuracy of regional and global vegetation and crop monitoring efforts.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Willem J. D. van Leeuwen, Alfredo R. Huete, Trevor W. Laing, and Kamel Didan "Vegetation change monitoring with spectral indices: the importance of view and sun angle standardized data", Proc. SPIE 3868, Remote Sensing for Earth Science, Ocean, and Sea Ice Applications, (17 December 1999); https://doi.org/10.1117/12.373099
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Cited by 1 scholarly publication.
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KEYWORDS
Sun

Vegetation

Reflectivity

Data modeling

Bidirectional reflectance transmission function

MODIS

Clouds

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