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Canadian Journal of Remote Sensing, 27, No.
2(2001), 143-158
SEASONAL CHANGES IN SUBARCTIC WETLANDS AND
RIVER ICE BREAKUP DETECTABLE ON RADARSAT IMAGES,
SOUTHERN HUDSON BAY LOWLAND,
ONTARIO, CANADA
M.A. MURPHY, I.P. MARTINI and R. PROTZ
Department of Land Resource Science,
University of Guelph, Guelph, ON, Canada N1G 2Wl
¡¡
 The objectives of this research were: to
analyze the backscatter response of RADARSAT to seasonal changes in wetlands of
southern Hudson Bay Lowland, northern Ontario, and to evaluate the potential of
RADARSAT images to monitor and perhaps predict ice-cover breakup of the upper
estuarine reaches of the Moose River. Six Standard- Mode images from May to
November 1996 were analyzed for the first objective. They show that seasonal
changes in moisture and surficial roughness, such as that associated with uneven
snow cover in treed areas, influenced back scatter more than incidence angle.
Backscatter increased from May to a June peak, and consistently decreased from
August to November. Five 1997 Fine-Mode images were used for the second
objective, bridging the May 1 river-ice-cover break- up. Backscatter from the
ice cover decreased 2 to 4 dB from three weeks prior to just before break-up.
Visually, the images record the progressive fracturing and shearing of the ice
cover; formation of leads, ice-push ridges, and the gradual change in ice
characteristics indicating increased wetness due either to melting or
fluvial-water flooding.
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