208
C. BERTOIA, J. FALKINGHAM, F. FETTERER
gray-scales. The early SARs suffered from very narrow swath widths (on the order of
So km) but by the end of the 1980s, lOo-km swath SARs were developed. This allowed
them to become practical for broad scale strategic ice mapping. In 1989, Canada introduced a routine airborne SAR ice reconnaissance service using a pair of X-band SARs
mounted on a Challenger jet aircraft. Each radar had a 100-km-wide swath with 2s-m
resolution. They were mounted on the aircraft to look at opposite sides of the flight
track, effectively providing a 200 km wide swath. The aircraft normally flew at an altitude of 3SOOO feet, well above any inclement weather, to provide an extremely reliable,
stable platform. The imagery from this system is still used as a benchmark against which
newer imagery sources are compared. Unfortunately, escalating costs and cheaper
alternatives forced the termination of this system on March 31, 1995.
After a lengthy development that had its roots in the SeaSat program, Canada
launched RADARSAT on November 4, 1995. It is the world's first radar satellite specifically designed for sea ice monitoring. Of primary significance for this role is its
ScanSAR mode, which provides a soo-km-wide swath with lOo-m resolution. This wide
swath provides a high repeat imaging capability, essential for operational sea ice monitoring. By virtue of this wide swath, RADARSAT can image every point on the earth's
surface north of 6SoN latitude at least once each day. North of 4SoN, the entire globe
can be imaged in 3 days or less. Imagery on demand, where and when required, is a
basic requirement for supporting operational activities where timing and location are
dictated by events, whether economic, military, or environmental, far beyond the control of the monitoring manager.
The CIS maintains a communications network that allows RADARSAT SAR data
acquired at both the Gatineau and Prince Albert station masks to be processed, geocoded, and delivered to a digital workstation environment called Ice Services Integrated
System (ISIS). This system merges ERDAS image processing software with ArcInfo
based GIS software. The ISIS software allows analysts to merge RADARSAT SAR with
aircraft SAR observations as well as NOAA AVHRR, ERS-2 SAR and DMSP SSM!I
imagery to produce complete ice charts. Ice charts and SAR images are transmitted to
Coast Guard icebreakers on demand using a digital satellite communications system
that employs significant data compression to keep data transfer times within reason.
Commercial ships receive ice charts via scheduled radio facsimile broadcasts as well as
on demand via Inmarsat facsimile.
10.3.3
Baltic Nations
Finland's ice service began in the 1890S but was not considered operational until World
War I, when ice charting began in order to secure marine transportation into Finland's
many ice-covered ports. During the November to May Baltic ice season, Finnish harbors
average some 20000 port calls, of which approximately sooo require icebreaker assistance.
The Finnish Ice Service operates under the Finnish Institute of Marine Research in
Helsinki. Daily ice charts are issued by facsimile and radio broadcast during the severe
portion of the ice season. Satellite data sources include NOAA AVHRR and ERS-1!-2
SAR images, which are supplemented with weekly visual aerial reconnaissance flights
from October through January. Observations are also received from 30 fixed ice thickness stations, icebreaker-based helicopters, and merchant vessels.
C. BERTOIA, J. FALKINGHAM, F. FETTERER
gray-scales. The early SARs suffered from very narrow swath widths (on the order of
So km) but by the end of the 1980s, lOo-km swath SARs were developed. This allowed
them to become practical for broad scale strategic ice mapping. In 1989, Canada introduced a routine airborne SAR ice reconnaissance service using a pair of X-band SARs
mounted on a Challenger jet aircraft. Each radar had a 100-km-wide swath with 2s-m
resolution. They were mounted on the aircraft to look at opposite sides of the flight
track, effectively providing a 200 km wide swath. The aircraft normally flew at an altitude of 3SOOO feet, well above any inclement weather, to provide an extremely reliable,
stable platform. The imagery from this system is still used as a benchmark against which
newer imagery sources are compared. Unfortunately, escalating costs and cheaper
alternatives forced the termination of this system on March 31, 1995.
After a lengthy development that had its roots in the SeaSat program, Canada
launched RADARSAT on November 4, 1995. It is the world's first radar satellite specifically designed for sea ice monitoring. Of primary significance for this role is its
ScanSAR mode, which provides a soo-km-wide swath with lOo-m resolution. This wide
swath provides a high repeat imaging capability, essential for operational sea ice monitoring. By virtue of this wide swath, RADARSAT can image every point on the earth's
surface north of 6SoN latitude at least once each day. North of 4SoN, the entire globe
can be imaged in 3 days or less. Imagery on demand, where and when required, is a
basic requirement for supporting operational activities where timing and location are
dictated by events, whether economic, military, or environmental, far beyond the control of the monitoring manager.
The CIS maintains a communications network that allows RADARSAT SAR data
acquired at both the Gatineau and Prince Albert station masks to be processed, geocoded, and delivered to a digital workstation environment called Ice Services Integrated
System (ISIS). This system merges ERDAS image processing software with ArcInfo
based GIS software. The ISIS software allows analysts to merge RADARSAT SAR with
aircraft SAR observations as well as NOAA AVHRR, ERS-2 SAR and DMSP SSM!I
imagery to produce complete ice charts. Ice charts and SAR images are transmitted to
Coast Guard icebreakers on demand using a digital satellite communications system
that employs significant data compression to keep data transfer times within reason.
Commercial ships receive ice charts via scheduled radio facsimile broadcasts as well as
on demand via Inmarsat facsimile.
10.3.3
Baltic Nations
Finland's ice service began in the 1890S but was not considered operational until World
War I, when ice charting began in order to secure marine transportation into Finland's
many ice-covered ports. During the November to May Baltic ice season, Finnish harbors
average some 20000 port calls, of which approximately sooo require icebreaker assistance.
The Finnish Ice Service operates under the Finnish Institute of Marine Research in
Helsinki. Daily ice charts are issued by facsimile and radio broadcast during the severe
portion of the ice season. Satellite data sources include NOAA AVHRR and ERS-1!-2
SAR images, which are supplemented with weekly visual aerial reconnaissance flights
from October through January. Observations are also received from 30 fixed ice thickness stations, icebreaker-based helicopters, and merchant vessels.