scribes the
lgorithms.
eir unique
Section 3
scribes the
ses of the
plored, as
f Radarsat
affect the
from this
Finally,
ctions that
iating the
resentative
Ice Centre
ch of the
ce Centre
am, 1993),
€ Radarsat,
the CCRS
al. 1987)
omparison
nd image,
coincident
ed in the
' polarized
variations
unction of
e type, ice
stics (i.e.
xist in the
| by; 1) the
| statistics
0 segment
lected for
parate ice
AR image.
Table 1 Dataset Characteristics
Location Ice Conditions Image Characteristics
& date
Grand Banks |e Predominant lead, surrounded by new, first year |e Variation in target response with range for both
East Coast, and brash ice. ice and water.
March 1989 |e Spring conditions, variably wet ice surface. Slight motion compensation error in near range.
Strong return (bright feature) from brash ice.
Weak return (dark feature) from wet ice surface.
Stronger return from open water in c-band than
x-band imagery.
Grand Banks
East Coast,
March 1989
e Same as Image 1.
Variation in target response with range for both
ice and water.
SAR illumination problems, particularly in the
near range.
Weak return (dark feature) from wet ice surface.
Beaufort Sea,
August 1992
Edge of arctic ice pack.
Ice Margin features; deteriorating wave broken
firstyear and multiyear floes.
e Pack ice features; conglomerate firstyear and
mulityear pack ice, with distinct ridging and
leads.
® Flooded and thin ice visible within leads.
e Strips of ice in open ocean.
Strong return (bright feature) from multiyear ice,
ridges and ice strips.
Low return (dark feature) from leads, open water
and flooded wave broken ice.
Moderate return from new ice within the leads.
Gulf of
St-Lawrence,
February
1993
* Highly mobile and dynamic ice conditions during
the winter ice advance.
* |ce consist mostly of new ice formations; grease
ice and nilas are visible.
e Some grey-white ice (exhibiting some structure)
is piled up behind madeleine island.
* Heavily rubbled ice is visible in Northumberland
Strait.
* Open water is present behind Madeleine island
and to the east of the ice edge.
Scene consists of two Star-2 overpasses
covering the entire Gulf region.
Fresh water ice (firstyear) from Saguenay river
gave a weak return (dark signature).
New ice, consisting of sub-resolution pancake
floes with raised edges generate a very strong
(bright feature) return.
Open water, nilas and grease ice generate a very
low return (dark return).
Barrow Strait
High Arctic,
August 1992
eo Summer break-up and outflow of ice from Barrow
Strait and adjoining channels into Lancaster
Sound.
e Large old floes are visible within broken/rubble
firstyear ice.
e Fastice is breaking out of the adjoining channels.
Large first year ice floes are not distinguishable
from large multiyear ice floes based on tone or
texture alone. They are distinguishable based on
shape due to surface wetness attenuating the
radar return.
Open water has a weak return (dark feature).
Rubble ice has a very strong return (bright
feature).
Jones Sound
High Arctic,
February
1990
e Consolidated mid-winter conditions.
Both multi-year, second year and thick first-year
ice present.
e Refrozen leads are visible within the multiyear
ice.
e Rubble fields are present.
Excellent example of variations in return from
same ice type; a second year floe appears mid-
toned, heavily ridged multiyear ice appears very
bright, while smooth multiyear ice appears dark.
Variation in signature is partly due to location in
range, is partly a function of the source of the
ice.
Refrozen leads and smooth firstyear ice have a
low return (dark feature).
Rubble fields have a strong return (bright
feature).
Labrador Sea,
January
1992
* Advancing winter ice edge.
* New ice, grey ice and strips and patches at edge.
e Thin first-year or grey-white ice within the pack.
e Open water visible as cracks within the pack, and
along advancing edge.
e Wave patterns visible with ice at margin.
Radar return fall off in near and far range, centre
of scene noticeably brighter.
Wave pattern noticeable by alternating strong
and weak return.
429
