Outline Of EPA Project
OBJECTIVES:
The overall objective of our project is to achieve an understanding of
the physical connections between canopy biochemistry, foliar reflectance
and remote sensing hyperspectral images.
The specific tasks are:
(1) evaluate the images from AVIRIS and assess the areal extent of
these marshes (understanding the resolution of AVIRIS and the current distributions
of the dominant plant species);
(2) determine the wavelength associated with the biochemical measured
from greenhouse and field experiments (analysis of active wavelength of
the biochemical compound absorbed), and quantify the relationship between
foliar and canopy spectra and the biochemical parameters of the plant community
in the wetlands (greenhouse and field experiments);
(3) determine the effect of the interactions among the factors (nitrate,
salinity and water level/redox potential) to the plant community of the
wetland through greenhouse and field experiments;
(4) assess the spatial and temporal variations in biomass and metabolite
production of the species in the study;
(5) develop the indicators for the wetland resources; The indicators
can be used to quantify the wetland plant community and to relate the information
of the biochemical parameters in the wetland community and remote sensing
data from AVIRIS (statistical work?).
RESULTS EXPECTED:
(1) spatial distributions:
a. boundary of the salt and tidal freshwater marshes.
b. dominant plant species in the marshes.
c. environmental gradients such as flooding, nitrogen, salinity and
pollutants.
(2) temporal distributions:
a. changes in the extent of the marshes (boundary change).
b. changes in the distribution of plant species.
c. changes in the environmental gradients.
(3) indices, biochemistry and estimates of production:
a. leaf area index, vegetation index (greenness), biochemistry, canopy
gap fraction and canopy closure.
b. estimates of salt marsh net primary production, photosynthesis,
absorbed photosynthetically active radiation (APAR).
(4) relationship between remote sensing image and the wetland plant
communities, relationship between remote sensing image and the environmental
gradients of nitrate, salinity and water level. Will reflectance a good
index for the linkage? Any others that exist in the literature or in anybody's
mind?
PROCEDURES:
(1) greenhouse experiment: experiment design (set ups) -- split-plot
or CRD?? three factors (salinity, nitrogen and water level); three replicates
?? measurements
a. parameters from plant sampling (what are they?)
b. chemical analyses (what are they?)
(2) field experiments: experiment design (set ups) -- ??? measurements
a. parameters from plant species list those from Eric's experiment
b. environmental variable samples including salinity, nitrogen and
water level. list these from Eric's experiment
(3) lab chemical analyses of samples from greenhouse and field experiments
(4) modeling effort in three levels of plants:
a. leaf structure (PROSPECT)
b. canopy structure (SAIL)
c. community structure
d. fate of environmental variables (such as nitrate model?).
(5) GIS grid display of the spatial distribution of the output from
the models
(6) remote sensing image analysis:
a. old index used to identify the salt marshes
b. new index should be developed to quantify the image from AVIRIS
and to relate to the model outputs based on the basic chemical, canopy
structure and environmental variables (nitrate, salinity and water level).
QUESTIONS:
(1) Were these models validated? Are PROSPECT and SAIL the only model
available to leaf and canopy reflectance?
(2) Are the measurements relevant to the inputs of leaf and canopy reflectance
models?
(3) How was the salt marshes classified? What index was used in general?
December 16, 1994
1998, Center for Spatial
Technologies and Remote Sensing (CSTARS)
University of California, Davis