212
C. BERTOIA, J. FALKINGHAM, F. FETTERER
(AARI) are used to automatically delineate ice concentration and ice floe size from visible imagery and to estimate ice thickness from wintertime infrared imagery. ArcInfo
GIS software is used to assimilate the data sources and produce the digital ice products. Composite ice charts and associated ice forecasts are issued every 7-10 days.
10.4
Radar Monitoring of Ice
10.4.1
Ice Reconnaissance: Aircraft SAR and Beyond
Radar has been used for operational ice reconnaissance since the early 1960s, when
search radars were installed on ice reconnaissance aircraft of the Canadian Ice Service.
In 1978, the United States introduced the first radar images from space when it launched
SEASAT, carrying an L-band SAR. Follow-on satellite SAR programs that were utilized
by operational ice centers included the European Space Agency's ERS-1 C-band SAR
and the Japanese L-band JERS-l. After a lengthy development cycle, Canada launched
RADARSAT, the world's first satellite specifically designed for sea ice monitoring. This
satellite, and its follow-on clone, RADARSAT-2, with their wide swath and fine resolution, will be the backbone of operational sea ice monitoring work for the next decade.
10.4.2
Processing and Communications
The major distinction between "operational" programs and other uses of remote sensing (such as research) is the requirement for timely delivery of data for operational decision making. This decision-making process is often time-critical and must consider
many disparate factors. For example, as a ship enters an ice-bound passage, the captain
must decide immediately which route will be least hazardous. With the existing potential that advected ice may damage rig equipment, the offshore drilling rig manager must
decide when to begin the lengthy process of hauling up a thousand meters of drill pipe
to move off-site. Ice is constantly in motion and even a few hours can dramatically
change its distribution in a local area. It is critical that the delay between imaging the
ice, creating an analysis or forecast, and putting the information into the decisionmakers'hands be short and within the timeframe that decisions are made. Remote sensing provides a tool that can help in the decision-making process, but it must perform
to demanding time standards.
In the early days of imaging radar use for ice reconnaissance, radars produced images
on plastic film aboard the aircraft. In order to provide t11e information to decisionmakers in a reasonable period of time, experts on board the aircraft analyzed t11e film
and plotted their analysis of the ice conditions on paper charts. These charts were
transmitted by radio facsimile to users operating in t11e ice below. This process resulted in a tremendous loss of information since the interpretation could not convey all of
the information gathered by t11e radar. In a few critical situations, the aircraft actually
dropped radar film onto t11e ice in the vicinity of a ship so that t11e navigators could
retrieve the film and the detail imaged by t11e radar. However, open cracks in t11e ice,
poor visibility, and polar bears, made t11is procedure much too risky to be employed
C. BERTOIA, J. FALKINGHAM, F. FETTERER
(AARI) are used to automatically delineate ice concentration and ice floe size from visible imagery and to estimate ice thickness from wintertime infrared imagery. ArcInfo
GIS software is used to assimilate the data sources and produce the digital ice products. Composite ice charts and associated ice forecasts are issued every 7-10 days.
10.4
Radar Monitoring of Ice
10.4.1
Ice Reconnaissance: Aircraft SAR and Beyond
Radar has been used for operational ice reconnaissance since the early 1960s, when
search radars were installed on ice reconnaissance aircraft of the Canadian Ice Service.
In 1978, the United States introduced the first radar images from space when it launched
SEASAT, carrying an L-band SAR. Follow-on satellite SAR programs that were utilized
by operational ice centers included the European Space Agency's ERS-1 C-band SAR
and the Japanese L-band JERS-l. After a lengthy development cycle, Canada launched
RADARSAT, the world's first satellite specifically designed for sea ice monitoring. This
satellite, and its follow-on clone, RADARSAT-2, with their wide swath and fine resolution, will be the backbone of operational sea ice monitoring work for the next decade.
10.4.2
Processing and Communications
The major distinction between "operational" programs and other uses of remote sensing (such as research) is the requirement for timely delivery of data for operational decision making. This decision-making process is often time-critical and must consider
many disparate factors. For example, as a ship enters an ice-bound passage, the captain
must decide immediately which route will be least hazardous. With the existing potential that advected ice may damage rig equipment, the offshore drilling rig manager must
decide when to begin the lengthy process of hauling up a thousand meters of drill pipe
to move off-site. Ice is constantly in motion and even a few hours can dramatically
change its distribution in a local area. It is critical that the delay between imaging the
ice, creating an analysis or forecast, and putting the information into the decisionmakers'hands be short and within the timeframe that decisions are made. Remote sensing provides a tool that can help in the decision-making process, but it must perform
to demanding time standards.
In the early days of imaging radar use for ice reconnaissance, radars produced images
on plastic film aboard the aircraft. In order to provide t11e information to decisionmakers in a reasonable period of time, experts on board the aircraft analyzed t11e film
and plotted their analysis of the ice conditions on paper charts. These charts were
transmitted by radio facsimile to users operating in t11e ice below. This process resulted in a tremendous loss of information since the interpretation could not convey all of
the information gathered by t11e radar. In a few critical situations, the aircraft actually
dropped radar film onto t11e ice in the vicinity of a ship so that t11e navigators could
retrieve the film and the detail imaged by t11e radar. However, open cracks in t11e ice,
poor visibility, and polar bears, made t11is procedure much too risky to be employed