EM 1110-2-2907
1 October 2003
of potential use. The method presented here details an important tool that may aid in haz-
ardous wintertime navigation and assist dam regulators on decisions regarding stream flow
and reservoir levels.
Point of Contact: Brian Tracy, Phone: (603) 646-4739
6-6 Case Study 4: Tree Canopy Characterization for EO-1 Reflective and
Thermal Infrared Validation Studies in Rochester, New York
Subject Area: Forestry and climate change
Purpose: To collect forest canopy structure and temperature data.
Data Set: Multispectral and hyperspectral
a. Introduction. Tree and forest structure respond strongly to environmental conditions
and change. Subsequently, studies have successfully shown the utility of remote sensing in
monitoring environmental conditions through the analysis of vegetation. The study reviewed
here surveyed a mixed forest in northern New York State in an attempt to better understand
the interaction between solar radiation and tree/forest structure. An additional objective of
this study was to validate the Earth Observing satellite (EO-1, launched in 2000). The vali-
dation was performed by comparing the EO-1 satellite data with that of the Landsat-7
ETM+ data. The EO-1 satellite acquired data at the same orbit altitude as Landsat-7 while
flying approximately 1 minute behind. EO-1 reflective bands were combined with the Land-
sat-7 ETM+ thermal infrared bands to estimate canopy temperature. The 1-minute delay in
synchronization between the two sensors was evaluated to test the effects of separating the
thermal and reflective measurements in time. Relating scene exitance (the radiative flux
leaving a point on a surface, moving in all directions) and reflectance to the landscape pro-
vided insight to prevailing environmental characteristics for the region.
b. Description of Methods. Ground and tree canopy data were collected from mature
healthy forest stands at a site in Durant-Eastman Park in Rochester, New York. Characteri-
zation of the forest included a stem and trunk survey, tree structure geometry measurements,
regional meteorology, and leaf area index (LAI) measurements (see http://www.uni-
sites, Ballard Ridge and Smith Grove, were selected for detailed study from within the lar-
ger forested area. Tree heights for both sites averaged 2030 m. Ballard Ridge consisted of a
dense mature stand of maple, cottonwood, elm, and oak trees. The Smith Grove consisted of
a dense mature stand of locust trees and cottonwood. Thermal and reflective spectral meas-
urements were made on leaves, tree bark, leaf litter, soil, and grass.
c. Field Work. Leaf area index (LAI) was calculated in the field with the use of a non-
imaging instrument, which measures vegetation radiation in the spectrum of 320490 nm.
Leaf area index is a ratio of the foliage area in a forest canopy relative to the ground surface
area. It estimates the photosynthetic capability of a forest. The measured light intensity was
used to calculate the average LAI for each location within the field site. High-resolution
hemispherical photographs were collected at each site using a digital camera with a fisheye
lens (148 field-of-view). The digital photographs were taken during the early morning and
6-10
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