Devon Island is situated in an isolated part of Canada's Nunavut Territory, and
is usually considered to be the largest uninhabited island in the world.
However, each summer since 1999, researchers from NASA's Haughton-Mars Project
and the Mars Society reside at this "polar desert" location to study the
geologic and environmental characteristics of a site which is considered to be
an excellent "Mars analog": a terrestrial location wherein specific conditions
approximate environmental features reported on Mars. Base camps established
amidst the rocks and rubble surrounding the Haughton impact crater enable
researchers to conduct surveys designed to test the habitat, equipment and
technology that may be deployed during a human mission to Mars. One of the many
objectives of the project scientists is to understand the ice formations around
the Haughton area, in the hopes that this might ultimately assist with the
recognition of areas where ice can be found at shallow depth on Mars.
These images of Devon Island from NASA's Multi-angle Imaging
SpectroRadiometer (MISR) instrument provide contrasting views of the spectral
and angular reflectance "signatures" of different surfaces within the region.
The top panel is a natural color view created with data from the red, green and
blue-bands of MISR's nadir (vertical-viewing) camera. The bottom panel is a
false-color multiangular composite of the same area, utilizing red band data
from MISR's 60-degree backward, nadir, and 60-degree forward-viewing cameras,
displayed as red, green and blue, respectively. In this representation, colors
highlight textural properties of elements within the scene, with blue tones
indicating smooth surfaces (which preferentially forward scatter sunlight) and
red hues indicating rougher surfaces (which preferentially backscatter). The
angular reflectance "signature" of low clouds causes them to appear purple, and
this visualization provides a unique way of distinguishing clouds from snow and ice.
The data were captured on June 28, 2001, during the early part of the arctic
summer, when sea ice becomes thinner and begins to move depending upon localized
currents and winds. In winter the entire region is locked with several meters of nearly motionless sea ice, which acts as a thermodynamic barrier to the loss of
heat from the comparatively warm ocean to the colder atmosphere. Summer melting
of sea ice can be observed at the two large, dark regions of open water; one is
present in the Jones Sound (near the top to the left of center), and another
appears in the Wellington Channel (left-hand edge). A large crack caused by
tidal heaving has broken the ice cover over the Parry Channel (lower right-hand
corner). A substantial ice cap permanently occupies the easternmost third of the island (upper right). Surface features such as dendritic meltwater channels
incised into the island's surface are apparent. The Haughton-Mars project site
is located slightly to the left and above image center, in an area which appears with relatively little surface ice, near the island's inner "elbow".
The images were acquired during Terra orbit 8132 and cover an area of about 334
kilometers x 229 kilometers. They utilize data from blocks 27 to 31 within World
Reference System-2 path 42.
Image credit: NASA/GSFC/LaRC/JPL, MISR Team.
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