8 Satellite Microwave Radar Observations of Antarctic Sea Ice
147
the first time, the launch of the European ERS-1 in July 1991 enabled compilation of the
first detailed picture of the C-band microwave backscattering characteristics of Southern Ocean sea ice. The launch of an identical ERS-2 in April 1995 provides continuity
in this series of Antarctic radar observations.
In this chapter, a variety of microwave data sets are presented and the results of these
combined data applied in investigations of the spatial and temporal characteristics of
sea ice. Since most field data collection and experiments coinciding with the ERS missions occurred within the South Atlantic quadrant of the Southern Ocean, this study
focuses particularly upon that Weddell Sea region.
8.2
Obtaining Spaceborne Radar Data in Antarctica
8.2.1
Antarctic SAR Data
The following sections briefly describe the data from currently operating SAR satellites, which can be received and recorded in Antarctica. Figure 1 shows the present locations of three operational Antarctic receiving stations.
8.2.1.1
ERS-l and ERS-2 SAR
Since 1991, the European Space Agency (ESA) ERS-1 and ERS-2 satellites have
acquired microwave radar image data of the Weddell Sea. The C-band imaging SAR
mode of the active microwave instrument (AMI) on board ERS allows vv-polarized
backscatter (cro vv) data to be collected (i.e. wavelength A = 5.6 cm). Presently, these
are the only operational instruments capable of acquiring high-resolution (approximately 30 m), all-weather (day or night), frequent repeat, 100 km-swath Antarctic
sea-ice images (Drinkwater 1995b). Neither spacecraft has SAR tape-recording capability and data access is limited to the areas of direct broadcast to existing operational and ESA-approved ERS-1 Antarctic ground receiving stations (ESA Earthnet
1992).
8.2.1.2
J-ERS-l SAR
Scientific data from the L-band (1.2-GHz) Japanese Earth Resources Satellite (J-ERS-1
or "Fuyo") SAR have been made available to approved investigators by the National
Space Development Agency (NASDA) of Japan. Currently, hh-polarized backscatter
(crohh) Antarctic data can only be acquired within the Syowa and McMurdo station mask
areas shown in Fig. 1. These SAR data may be ordered at "research" cost from RESTEC
(Remote Sensing Technology Centre; i.e., the distribution agent for NASDA) through a
research data distribution and purchase agreement.
147
the first time, the launch of the European ERS-1 in July 1991 enabled compilation of the
first detailed picture of the C-band microwave backscattering characteristics of Southern Ocean sea ice. The launch of an identical ERS-2 in April 1995 provides continuity
in this series of Antarctic radar observations.
In this chapter, a variety of microwave data sets are presented and the results of these
combined data applied in investigations of the spatial and temporal characteristics of
sea ice. Since most field data collection and experiments coinciding with the ERS missions occurred within the South Atlantic quadrant of the Southern Ocean, this study
focuses particularly upon that Weddell Sea region.
8.2
Obtaining Spaceborne Radar Data in Antarctica
8.2.1
Antarctic SAR Data
The following sections briefly describe the data from currently operating SAR satellites, which can be received and recorded in Antarctica. Figure 1 shows the present locations of three operational Antarctic receiving stations.
8.2.1.1
ERS-l and ERS-2 SAR
Since 1991, the European Space Agency (ESA) ERS-1 and ERS-2 satellites have
acquired microwave radar image data of the Weddell Sea. The C-band imaging SAR
mode of the active microwave instrument (AMI) on board ERS allows vv-polarized
backscatter (cro vv) data to be collected (i.e. wavelength A = 5.6 cm). Presently, these
are the only operational instruments capable of acquiring high-resolution (approximately 30 m), all-weather (day or night), frequent repeat, 100 km-swath Antarctic
sea-ice images (Drinkwater 1995b). Neither spacecraft has SAR tape-recording capability and data access is limited to the areas of direct broadcast to existing operational and ESA-approved ERS-1 Antarctic ground receiving stations (ESA Earthnet
1992).
8.2.1.2
J-ERS-l SAR
Scientific data from the L-band (1.2-GHz) Japanese Earth Resources Satellite (J-ERS-1
or "Fuyo") SAR have been made available to approved investigators by the National
Space Development Agency (NASDA) of Japan. Currently, hh-polarized backscatter
(crohh) Antarctic data can only be acquired within the Syowa and McMurdo station mask
areas shown in Fig. 1. These SAR data may be ordered at "research" cost from RESTEC
(Remote Sensing Technology Centre; i.e., the distribution agent for NASDA) through a
research data distribution and purchase agreement.