Surface brightness contrasts accentuated by a thin layer of snow enable
a network of rivers, roads, and farmland boundaries to stand out clearly
in these Multi-angle Imaging Spectroradiometer (MISR) images of
southeastern Saskatchewan and southwestern
Manitoba. The lefthand image is a multi-spectral false-color view made
from the near-infrared, red, and green bands of MISR's vertical-viewing
(nadir) camera. The righthand image is a multi-angle false-color view
made from the red band data of the 60-degree aftward camera, the nadir
camera, and the 60-degree forward camera. In each image, the selected
channels are displayed as red, green, and blue, respectively. The data
were acquired April 17, 2001, and cover an area
measuring about 285 kilometers x 400 kilometers. North is at the top.
The junction of the Assiniboine and Qu'Apelle Rivers in the bottom part
of the images is just east of the Saskatchewan-Manitoba border. During
the growing season, the rich, fertile soils in this area support
numerous fields of wheat, canola, barley, flaxseed, and rye. Beef cattle
are raised in fenced pastures. To the north, the terrain becomes more
rocky and forested. Many frozen lakes are visible as white patches in
the top right. The narrow linear, north-south trending patterns about a
third of the way down from the upper right corner are snow-filled
depressions alternating with vegetated ridges, most probably carved by
glacial flow.
In the lefthand image, vegetation appears in shades of red, owing to its
high near-infrared reflectivity. In the righthand image, several
forested regions are clearly visible in green hues. Since this is a
multi-angle composite, the green arises not from the color of the leaves
but from the architecture of the surface cover. Progressing
southeastward along the Manitoba Escarpment, the forested areas include
the Pasquia Hills, the Porcupine Hills, Duck Mountain Provincial Park,
and Riding Mountain National Park. The forests are brighter in the nadir
than at the oblique angles, probably because more of the snow-covered
surface is visible in the gaps between the trees. In contrast, the
valley between the Pasquia and Porcupine Hills near the top of the
images appears bright red in the lefthand image (indicating high
vegetation abundance) but shows a mauve color in the multi-angle view.
This means that it is darker in the nadir than at the oblique angles.
Examination of imagery acquired after the snow has melted should
establish whether this difference is related to the amount of snow on
the surface or is indicative of a different type of vegetation
structure.
Saskatchewan and Manitoba are believed to derive their names from the
Cree words for the winding and swift-flowing waters of the Saskatchewan
River and for a narrows on Lake Manitoba where the roaring sound of wind
and water evoked the voice of the Great Spirit. They are two of Canada's
Prairie Provinces; Alberta is the third.
Image courtesy NASA/GSFC/LaRC/JPL, MISR Team.