Ice island detection and characterization with airborne synthetic aperture radar
- Univ. of Alaska, Fairbanks (United States)
A 1:300,000 scale airborne synthetic aperture radar (SAR) image of an area of the Arctic Ocean adjacent to the Queen Elizabeth Islands, Canadian High Arctic, is examined to determine the number and characteristics of ice islands in the image and to assess the capability of airborne and satellite SAR to detect ice islands. Twelve ice islands have been identified, and their dimensions range from as large as 5.7 km by 8.7 km to as small as 0.15 km by 0.25 km. A significant SAR characteristic of the shelf ice portions of ice islands is a return with a ribbed texture of alternating lighter and darker grey tones resulting from the indulating shelf ice surfaces of the ice islands. The appearance of the ribbed texture varies according to the ice islands' orientation relative to the illumination direction and consequently the incidence angle. Some ice islands also include extensive areas of textureless dark tone attached to the shelf ice. The weak returns correspond to (1) multiyear landfast sea ice that was attached to the front of the Ward Hunt Ice Shelf at the time of calving and which has remained attached since then and (2) multiyear pack ice that has become attached and consolidated since the calving, indicating that ice islands can increase their area and mass significantly as they drift. Ice islands are easily discernible in SAR images and for the future SAR represents a promising technique to obtain a census of ice islands in the Arctic Ocean. However, any SAR-based census probably will be conservative because ice islands smaller than 300-400 m across are likely to remain undetected, particularly in areas of heavy ice ridging which produces strong SAR clutter.
- OSTI ID:
- 5074682
- Journal Information:
- Journal of Geophysical Research; (United States), Vol. 95:C4; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ICEBERGS
MONITORING
SYNTHETIC-APERTURE RADAR
PERFORMANCE
AIRCRAFT
ARCTIC OCEAN
COMPARATIVE EVALUATIONS
DETECTION
DIMENSIONS
INVENTORIES
SATELLITES
TEXTURE
EVALUATION
ICE
MEASURING INSTRUMENTS
RADAR
RANGE FINDERS
SEAS
SURFACE WATERS
540310* - Environment
Aquatic- Basic Studies- (1990-)