F. CARSEY, R. HARDING, C. WALES
ice and ocean-atmosphere conditions, and SAR observations have proved quite useful
in the identification of ice features that are of operational importance, such as ridges
and leads, and for determinations of ice motion, which can lead to dramatic changes
of conditions. ASF supports operations in ice-covered seas through the generation of
«Quick-Look" data for NOAA and other users. At present this data support is limited to
the region of the Alaska mask (see Fig. 1), but it will eventually be extended to include
most of the ice-covered seas of the northern and southern hemispheres.
9.4
ASF Plans in Sea Ice Science and Operations Support
Sea ice observations continue to be a prime science objective of ASP. Among the recently
named Applications, Development and Research teams are 13 sea ice and 2 lake ice projects
(out of a total of 60 projects). In addition, operational requirements from the National
Oceanic and Atmospheric Administration (NOAA) and NASA call for extensive SAR mapping of sea ice. While the relative importance of sea ice and polar ocean work has declined
due to the growth of other SAR applications, the SAR applications to sea ice remain the
central task of ASF, and this situation is not seen as likely to change in the near future. The
highest priority at ASF is the support of sea ice data for science and operations.
The top long-term priority of ASF is obtaining mapping coverage of the Arctic Sea
ice on approximately a weekly basis; this coverage is called the ''Arctic Snapshot:' as
shown in Fig. 2. To produce a predictable data set, the Arctic Snapshot will be acquired
four times every 6 days per 24-day RADARSAT orbit cycle (An orbit cycle is the time
required for the orbit to repeat; for RADARSAT the orbit of day 1 is identical to that of
day 25.) This pattern means that data takes for every 24-day period are identical. The
Arctic Snapshot is a high-priority data product for ASF, but regular production must
await the working out of data transfer details. It is hoped that the Arctic Snapshot will
be acquired and archived by the start of calendar 1997 or sooner.
ASF currently plans to operate RGPS and archive both the input and product data
streams after operation begins sometime in 1997 or 1998.
Marine operations support in the northern hemisphere consists largely of timely sea
ice data from the Arctic Snapshot. In the part of the Southern Ocean that is in the
McMurdo station mask as shown in Fig. 2, there is no commercial shipping at this time.
However, research and support vessels are in these waters quite regularly, and these ships
require good information on ice conditions for the safety of vessel and crew, and ASF
anticipates that this support will become a part of its regular activities in future. The
job of getting SAR data from McMurdo to ASF for processing and back to McMurdo,
and to the ships plying the Ross Sea and neighboring waters, is substantial, and a start
on that job has begun with the installation of high-speed satellite communications
equipment at Black Island near McMurdo. The remainder of the communications linkages to supply SAR ice data to ships will require a little more time to develop.
9.5
Long-Term View and Future Instruments
Successful SAR-based research projects have been conducted with ERS-1 and -2 and
JERS-1, other projects are in advanced planning for RADARSAT, and experienced SAR
ice and ocean-atmosphere conditions, and SAR observations have proved quite useful
in the identification of ice features that are of operational importance, such as ridges
and leads, and for determinations of ice motion, which can lead to dramatic changes
of conditions. ASF supports operations in ice-covered seas through the generation of
«Quick-Look" data for NOAA and other users. At present this data support is limited to
the region of the Alaska mask (see Fig. 1), but it will eventually be extended to include
most of the ice-covered seas of the northern and southern hemispheres.
9.4
ASF Plans in Sea Ice Science and Operations Support
Sea ice observations continue to be a prime science objective of ASP. Among the recently
named Applications, Development and Research teams are 13 sea ice and 2 lake ice projects
(out of a total of 60 projects). In addition, operational requirements from the National
Oceanic and Atmospheric Administration (NOAA) and NASA call for extensive SAR mapping of sea ice. While the relative importance of sea ice and polar ocean work has declined
due to the growth of other SAR applications, the SAR applications to sea ice remain the
central task of ASF, and this situation is not seen as likely to change in the near future. The
highest priority at ASF is the support of sea ice data for science and operations.
The top long-term priority of ASF is obtaining mapping coverage of the Arctic Sea
ice on approximately a weekly basis; this coverage is called the ''Arctic Snapshot:' as
shown in Fig. 2. To produce a predictable data set, the Arctic Snapshot will be acquired
four times every 6 days per 24-day RADARSAT orbit cycle (An orbit cycle is the time
required for the orbit to repeat; for RADARSAT the orbit of day 1 is identical to that of
day 25.) This pattern means that data takes for every 24-day period are identical. The
Arctic Snapshot is a high-priority data product for ASF, but regular production must
await the working out of data transfer details. It is hoped that the Arctic Snapshot will
be acquired and archived by the start of calendar 1997 or sooner.
ASF currently plans to operate RGPS and archive both the input and product data
streams after operation begins sometime in 1997 or 1998.
Marine operations support in the northern hemisphere consists largely of timely sea
ice data from the Arctic Snapshot. In the part of the Southern Ocean that is in the
McMurdo station mask as shown in Fig. 2, there is no commercial shipping at this time.
However, research and support vessels are in these waters quite regularly, and these ships
require good information on ice conditions for the safety of vessel and crew, and ASF
anticipates that this support will become a part of its regular activities in future. The
job of getting SAR data from McMurdo to ASF for processing and back to McMurdo,
and to the ships plying the Ross Sea and neighboring waters, is substantial, and a start
on that job has begun with the installation of high-speed satellite communications
equipment at Black Island near McMurdo. The remainder of the communications linkages to supply SAR ice data to ships will require a little more time to develop.
9.5
Long-Term View and Future Instruments
Successful SAR-based research projects have been conducted with ERS-1 and -2 and
JERS-1, other projects are in advanced planning for RADARSAT, and experienced SAR