Utilization
of VEGETATION Data To Extract Effective Surface
Parameters
Principal Investigator: Jiaguo Qi
Vegetation is a key parameter in the functioning of
hydrological processes occurring within the
earth-atmosphere interface and is, therefore, a
sensitive indicator for environmental and global
changes. Continuous monitoring of vegetation
variation at regional to global scale provides
useful clues concerning our changing environment.
Remote sensing provides a means to monitor changes
in the amount of vegetation in a qualitative manner
for homogenous surfaces. Quantitative estimates of
vegetation of especially heterogeneous surfaces are established in order to fully understand and
predict the future trend of our changing
environment. The VEGETATION instrument
included on board the SPOT 4 satellite provides
a unique data set due to its frequent and large
spatial coverage, sensitive spectral bands for
vegetation and atmosphere, and particularly its
multidirectional capability. The VEGETATION data
consequently provides scientists an opportunity
to fully investigate the feasibility of
quantitatively extracting physical or biophysical
properties of terrestrial land surfaces. In this
project, we launched an investigation that utilizes
the VEGETATION data to quantitatively estimate
surface physical parameter such as vegetation
percentage cover and leaf area index (LAI) and
developed an operational approach to monitor
vegetation at regional to global scales. We use
well- controlled ground data sets and satellite data
to first quantify the noise levels from atmosphere
and soil background, and BRDF models to quantify the
bidirectional effect. In a second step, we defined effective surface physical parameters at
regional to global scales and establish a
quantitative relationship between the effective
surface physical parameters and VEGETATION data by
modeling physical processes of radiation regime
within the earth- atmosphere interface. The approach
is simple and within a reasonable noise level,
allows an operational use of VEGETATION data
products for vegetation monitoring. The outcome of
this project includes: generation of an
operational algorithm specifically designed to
quantitatively extract surface (heterogeneous)
physical parameters with the VEGETATION data sets;
definition of effective surface parameters
retrievable with VEGETATION data; and quantification
of noise levels.
The Center for Global Change & Earth Observations, Michigan
State University
218 Manly Miles Building, 1405 S. Harrison Road, East
Lansing, Michigan 48823, Phone: (517) 432-7774
