A newly-released data product from NASA's Multi-angle Imaging
SpectroRadiometer (MISR) is currently being examined by the
Queensland Department of Natural Resources and Mines (DNRM),
Australia, with the intent of utilizing multiangle and
multispectral information to assess the structural properties of
vegetation and improve the mapping and monitoring of forest and
woodland areas. The new product consists of "Local Mode" high-
resolution image data, which provide 275-meter spatial resolution
georectified imagery in all 36 channels (nine cameras x four
spectral bands) of the instrument, for selected target areas.
This contrasts with the otherwise continual Global Mode data,
which provides imagery at 1.1-kilometer resolution in 24 of the
36 channels, and 275-meter resolution in the other 12. Since the
beginning of the Terra mission, Local Mode data have been
routinely acquired for dozens of targets around the globe, and
the software to generate georectified imagery systematically from
these data has recently become operational at the NASA Langley
Atmospheric Sciences Data Center, where MISR's standard data
products are created.
Surface changes across the Southern Brigalow Belt in central
Queensland are illustrated by these six image panels acquired by
MISR on June 7 (left) and September 27 (right), 2003, during the
austral winter and spring seasons, respectively. This is the
region of study for the pilot phase of a project conducted by
Queensland's Statewide Landcover and Trees Study (SLATS). SLATS is using MISR Local Mode
data to assess the relationship between multiangular reflectance
and structural properties of forests and woodlands across the
state.
The top panels display data from the near-infrared, red and green
spectral bands of MISR's vertical-viewing (nadir) camera as red,
green and blue, respectively, causing highly vegetated areas to
appear red. Above image center, the area of the densely vegetated
Carnarvon Gorge National Park appears very bright at the
near-infrared spectral band. In the lower left, the Warrego River
flows southward through grassland areas toward the Murray-Darling
river system. In several areas, particularly along the right-hand
portion of the images, a reduction in photosynthetic activity for
pastures and/or grasslands is indicated between the winter and
spring dates due to a dry spring.
The central panels are multi-angular composites in which data
from the near-infrared band of MISR's 60° forward, nadir, and 60°
backward viewing cameras are displayed as red, green and blue,
respectively. The bottom panels display red-band data in the same
configuration from the same cameras. Within the composites, color
variations serve as a proxy for changes in angular reflectance,
which are in turn influenced by vegetation structure, terrain and
soil type, and by the different solar illumination conditions on
the two dates. In the near-infrared band composites the Carnarvon
Gorge area appears almost uniformly bright because of high
transmittance of the leaves at near-infrared wavelengths and
relatively low angular variation. This area appears dark in the
red multiangle composites due to high absorption at the red band
from the relatively uniform, dense tree canopy. In other words,
sunlight at near-infrared wavelenths is strongly scattered
between the leaf layers of the dense canopies, and the influence
of shadows between the tree crowns is less pronounced compared
with open woodlands.
The Multiangle Imaging SpectroRadiometer observes the daylit
Earth continuously and every 9 days views the entire globe
between 82° north and 82° south latitude. These
data products were generated from a portion of the imagery
acquired during Terra orbits 18460 and 20091. The panels cover an
area of 256 kilometers x 247 kilometers, and utilize data from
blocks 110 to 112 within World Reference System-2 path 93.
MISR was built and is managed by NASA's Jet Propulsion Laboratory,
Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The
Terra satellite is managed by NASA's Goddard Space Flight Center,
Greenbelt, MD. JPL is a division of the California Institute of
Technology.
Image credit: NASA/GSFC/LaRC/JPL, MISR Team.
Text acknowledgment: Clare Averill (Raytheon / Jet Propulsion Laboratory) and John Armston (SLATS Team, Department of Natural Resources and Mines, Queensland).
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