| Mackenzie Delta, Northwest Territories |
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Natural Resources Canada > Earth Sciences Sector > Priorities > Canada Centre for Remote Sensing
Tour Canada from space Mackenzie Delta, Northwest Territories
 Canada's longest river, the Mackenzie River, empties into the cold Beaufort Sea (A) in a region known as the Mackenzie Delta. Sediments laid down by the river over the past 7000 years have created a vast delta 13,500 km2 in area. Diverse populations of birds and fish and several northern communities call this complex and dynamic mixture of lakes, rivers and flood plains home. RADARSAT-1 satellite imagery allow scientists to map vegetation growth and to monitor important, rapid processes like spring ice breakup and overland flooding - two common events that occur in the dynamic spring period. This monitoring helps us to understand how different delta components (i.e. hydrology, geology, biology) work together and how they might react to environmental change brought on by changes in climate (e.g. global warming) and/or resource development (e.g. oil and gas production).
Question: Can you explain why the water in the western portion of Shallow Bay (B) appears darker than the adjacent waters of Mackenzie Bay and the Beaufort Sea? [ Answer ]
About this Image
| Location: |
Mackenzie Delta, Northwest Territories |
| NTS map(s): |
107 B, C; 117 A, D |
 Location Map: |
See a detailed map (1:1M) of the region |
| Image Date: |
July 22, 1997 |
| Satellites/Sensors: |
RADARSAT SAR Wide 2 mode |
| Resolution: |
200 m pixels |
| Image Area: |
150 km x 144 km |
| Image Features: |
Mackenzie Delta, delta plain, sea ice, flooded land, cotton grass, thermokarst lakes, mud flats |
| Related Tour Images: |
Rankin Inlet, Nunavut; Toronto, Ontario; Labrador Sea, Newfoundland |
| Related Glossary Terms: |
These terms from the CCRS Glossary may help you to understand this image and its interpretation:
backscatter, diffuse reflection, specular reflection, corner reflector, RADARSAT, SAR |
| Related Tutorial Sections: |
These sections of the "Fundamentals of Remote Sensing" tutorial by CCRS will help you to better understand this image and its interpretation:
1.6 3.0 5.6
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| Image Credits: |
Received and analyzed by the Canada Centre for Remote Sensing
Pre-processed by RADARSAT International Inc.
Source image © Canadian Space Agency |
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Additional
Information: |
The active Mackenzie Delta and the adjacent older tundra landscape of Richards Island (C) and the Caribou Hills (D) are clearly separable in this RADARSAT Wide mode image. The saturated, grassy delta of the active delta (E) generally appears brighter than the drier, relatively smoother tundra (C, D). The dark black areas indicate water bodies with smooth surfaces that scatter energy away from the sensor. The thermokarst lakes of the tundra, the myriad of outlet channels/lakes in the active delta and the Beaufort Sea coastline are quite visible in this image. Differences in image tone within the active delta area indicate variations in vegetation cover. The lower delta (northern portion) consists mainly of sedge-cotton grass meadows (bright tones). Drier areas, such as channel levees contain willow and alder trees and appear as darker areas in the image. The darker areas in the south portion of the active delta mark the most northern extent of the white spruce in Canada. Due to its sensitivity to moisture content and surface roughness, RADARSAT can be used effectively to map vegetation distribution in the delta. |
| Question: |
Can you explain why the water in the western portion of Shallow Bay (B) appears darker than the adjacent waters of Mackenzie Bay and the Beaufort Sea? |
| Answer: |
This can be explained by a well-known phenomenon in SAR imagery of coastal areas known as wind sheltering from land. Adjacent highlands to the west of the bay shelter the water surface from the wind and thus reduce the generation of surface waves. This results in a smooth surface that scatters much of the scattered signal away from the sensor, resulting in a dark tone. Higher wind speeds and wave heights in the open adjacent waters return more signal to the sensor, thus resulting in brighter image tones. |
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