Study of atmospheric and bidirectional effects on surface reflectance and vegetation index time series: Application to NOAA AVHRR and preparation for future space missions. Final report

Technical Report · Tue Jun 01 04:00:00 EDT 1993

OSTI ID:6209194

Frouin, R

The objectives of the investigation, namely to characterize the atmospheric and directional effects on surface reflectance and vegetation index using the First International Satellite Cloud Climatology Project (ISLCSP) Field Experiment (FIFE) data set, develop new algorithms to obtain better Advanced Very High Resolution Radiometer (AVHRR) indices, and define possible improvements for future satellite missions, were addressed in three separate, yet complementary studies. First, it was shown, from theoretical calculations, that visible and near infrared reflectances combined linearly at optimum (one or two) viewing angles relate linearly to the fraction of photosynthetically available radiation absorbed by plants, f[sub par], can be used independently of the type of foliage and substrate, eliminate the effects of sub-pixel spatial heterogeneity, and improve the accuracy of the f[sub par] estimates when compared to the Normalized Difference Vegetation Index, NDVI. Second, it was demonstrated that NDVI, even though it is not a linear combination of radiances or reflectances, can be spatially integrated without significant loss of information from scales of 300 to 1000 m. Third, AVHRR visible and near-infrared reflectances over the FIFE site, separating temporal and bidirectional components and determining the model parameters through an original iterative scheme was successfully modeled. It appears that NDVI generated from the top-of-atmosphere reflectances normalized by the bidirectional effects (as determined in the scheme) is a better vegetation index than maximum NDVI. Details about the three studies are presented.

• Research Organization: Scripps Institution of Oceanography, La Jolla, CA (United States)
• OSTI ID: 6209194
• Report Number(s): N-93-28417; NASA-CR--193158; NAS--1.26:193158; CNN: NAGW-1968
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540210* -- Environment
Terrestrial-- Basic Studies-- (1990-)
ALGORITHMS
MATHEMATICAL LOGIC
MATHEMATICS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLANTS
RADIATIONS
REMOTE SENSING
SOLAR RADIATION
SPECTRAL REFLECTANCE
STELLAR RADIATION
SURFACE PROPERTIES
TIME-SERIES ANALYSIS