Geology Reference
In-Depth Information
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Multi-year pack ice
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RADARSAT- 2 Data and Products C Max DONALD DETTWLER AND ASSOCIATES LT D,
2011-All Rights Reseved RADARSAT is an effced mark of D+ Canadian Space Agency
Donodes of products de RADARSAT- 2 O MacDONALD, DETTWLER AND ASSOCIATES LT D,
2011-toes drods reseved. RADARSAT est one mar2quet officiede de Agence
spaticale canadian.
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Figure 11.11
Radarsat‐2 mosaic of the western Arctic region, part of the Arctic atlas 2011 compiled from images
acquired in January/February 2011. All the Radarsat‐2 images are the property of the MacDonald, Dettwiler, and
Associates Ltd. (MDA).
identify overall trends or synoptic‐scale conditions. That
is because the IAPs can be very large; their typical dimen-
sions vary from a few kilometers to a few tens of kilom-
eters, depending on the subjective estimate of the ice
analyst. Since one code of ice parameters is assigned to
the entire polygon with the assumption of the uniform
distribution of the parameters across the polygon, the
subpolygon details are missing in the charts. Therefore,
the use of the charts to verify information obtained from
any data source that has resolution finer than the size
of the polygon (e.g., remote sensing observations from
passive or active microwave data) should proceed with
caution because it will reveal the heterogeneity of the
parameter distribution within the polygon. This limita-
tion applies also to operational use of the information
in the chart since the exact locations of the hazardous
ice inside the polygon cannot be determined (only the
average percentage of hazardous ice is given).
The CIS issue an annual “Ice Atlas” of the Canadian
Arctic from a mosaic of Radarsat images. This has been
produced since 1990. Prior to the operational use of
Radarsat in 1996, round‐robin flights of an airborne SAR
were used (the STAR‐2 system mounted on the Intera's
Challenger
aircraft as mentioned before) were used. The
airborne survey, however, did not cover the entire region
and it was very expensive. Radarsat‐1 was used to generate
the annual atlas until 2006. Later Radarsat‐2 has been the
prime sensor used to generate this product while Radarsat‐1
was used until its decommission in 2013 to fill occasional
gaps. The mosaic is compiled from tens of orbits acquired
in the January/February time frame. The main objective is
to maintain a climatological archive of Arctic winter ice in
order to follow variations in ice geographically, seasonally,
and annually. Data are usually resampled to approximately
800 m pixels. Figure 11.11 shows the part of the mosaic of
the western Arctic region.
