10 Polar SAR Data for Operational Sea Ice Mapping
203
compiled into a volume including illustrative sea ice photographs and was issued as a
publication entitled WMO Sea-ice Nomenclature (Publication No 259) in 1970. It
remains the accepted standard for ice mapping terminology and symbology today.
10.3
Ice Information Services Throughout the World
10.3.1
United States of America
Interest in developing accurate methods for tracking and forecasting of sea ice conditions in the US began in 1952. US Navy interests in the Arctic ice pack conditions were
fueled by the need to establish and maintain distant early warning stations scattered
across the high Arctic. In 1951,30 ships of the 33 vessel group operating under the code
name Operation Bluejay were damaged by harsh ice conditions while attempting to navigate along the west coast of Greenland to establish the distant early-warning station
and air base at Thule, Greenland (McDowell 1990 ). The identification of new requirements for accurate sea ice observation and forecasting resulted in the 1952 establishment of an ice division at the US Naval Oceanographic Office. In 1958, the first ice mission under the North Pole was accomplished by the submarine USS Nautilus. A 1961
USS Sargo deployment resulted in a collision with an ice keel and damage to tlle submarine's sail (McDowell 1990). These events resulted in greater interest in developing
capabilities to analyze ice conditions and led to the development of the Naval Polar
Oceanography Center in 1972. After a merger with the National Oceanic and Atmospheric Administration (NOAA) in 1976, the organization became the Navy/NOAA Joint
Ice Center. This center was tasked with providing global sea ice and Great Lakes ice data
to military, government, foreign, and commercial customers (Benner and Bertoia
1992). The organizations were joined by the US Coast Guard in 1995 to form the US
National Ice Center (NIC).
The NIC has global responsibility for providing ice information for all sea-ice-covered waters, and lake ice mapping of tlle Great Lakes. Ice analysis is accomplished in a
digital workstation environment using data from polar-orbiting satellites, meteorological models, drifting buoys, aerial ice reconnaissance, and ship and shore station
reports. The primary data source for ice analysis in the early years was observation from
aircraft. In 1972, the launch of polar orbiting satellites by NOAA led to ice analysis
derived from visible and infrared imagery. The NIC currently uses the sensors aboard
both the NOAA TIROS-N and the Defense Meteorological Satellite Program (DMSP)
platforms. Ice analysis from visible and infrared imagery is highly subjective; images
have fairly coarse resolution (0.55-1.1 km) and are subject to lack of solar illumination
during the polar night. Climatologically, extensive cloud cover obscures the ice pack
nearly 80% of the time during the summer months (Benner and Bertoia 1992). These
limitations have led to the increased reliance on sensors from tlle microwave portion
of the electromagnetic spectrum.
The first sensor to provide day/night, weather independent, operationally available
imaging of sea ice was the DMSP Electronically Scanning Microwave Radiometer
(ESMR), which flew from 1973 to 1976. This sensor was replaced by the Scanning Multichannel Microwave Radiometer which flew from 1978 to 1987. The microwave
203
compiled into a volume including illustrative sea ice photographs and was issued as a
publication entitled WMO Sea-ice Nomenclature (Publication No 259) in 1970. It
remains the accepted standard for ice mapping terminology and symbology today.
10.3
Ice Information Services Throughout the World
10.3.1
United States of America
Interest in developing accurate methods for tracking and forecasting of sea ice conditions in the US began in 1952. US Navy interests in the Arctic ice pack conditions were
fueled by the need to establish and maintain distant early warning stations scattered
across the high Arctic. In 1951,30 ships of the 33 vessel group operating under the code
name Operation Bluejay were damaged by harsh ice conditions while attempting to navigate along the west coast of Greenland to establish the distant early-warning station
and air base at Thule, Greenland (McDowell 1990 ). The identification of new requirements for accurate sea ice observation and forecasting resulted in the 1952 establishment of an ice division at the US Naval Oceanographic Office. In 1958, the first ice mission under the North Pole was accomplished by the submarine USS Nautilus. A 1961
USS Sargo deployment resulted in a collision with an ice keel and damage to tlle submarine's sail (McDowell 1990). These events resulted in greater interest in developing
capabilities to analyze ice conditions and led to the development of the Naval Polar
Oceanography Center in 1972. After a merger with the National Oceanic and Atmospheric Administration (NOAA) in 1976, the organization became the Navy/NOAA Joint
Ice Center. This center was tasked with providing global sea ice and Great Lakes ice data
to military, government, foreign, and commercial customers (Benner and Bertoia
1992). The organizations were joined by the US Coast Guard in 1995 to form the US
National Ice Center (NIC).
The NIC has global responsibility for providing ice information for all sea-ice-covered waters, and lake ice mapping of tlle Great Lakes. Ice analysis is accomplished in a
digital workstation environment using data from polar-orbiting satellites, meteorological models, drifting buoys, aerial ice reconnaissance, and ship and shore station
reports. The primary data source for ice analysis in the early years was observation from
aircraft. In 1972, the launch of polar orbiting satellites by NOAA led to ice analysis
derived from visible and infrared imagery. The NIC currently uses the sensors aboard
both the NOAA TIROS-N and the Defense Meteorological Satellite Program (DMSP)
platforms. Ice analysis from visible and infrared imagery is highly subjective; images
have fairly coarse resolution (0.55-1.1 km) and are subject to lack of solar illumination
during the polar night. Climatologically, extensive cloud cover obscures the ice pack
nearly 80% of the time during the summer months (Benner and Bertoia 1992). These
limitations have led to the increased reliance on sensors from tlle microwave portion
of the electromagnetic spectrum.
The first sensor to provide day/night, weather independent, operationally available
imaging of sea ice was the DMSP Electronically Scanning Microwave Radiometer
(ESMR), which flew from 1973 to 1976. This sensor was replaced by the Scanning Multichannel Microwave Radiometer which flew from 1978 to 1987. The microwave