Margin of the Antarctic ice cover derived from Synthetic Aperture Radar images for the sector 79E-108E

Geographic location of the outer margin of the Antarctic ice cover for the sector between longitudes 79E and 108E, including margins of ice shelves, glaciers, and iceberg tongues. The data set does not in general include the grounding zone at the inland margin of the ice shelves or glaciers.\r\n\r\nThe margin was defined by interpretation of an image mosaic generated from Synthetic Aperture Radar data. The image mosaic was built using navigation data accompanying the SAR images to transform the images to a map projection. The image navigation data were adjusted so that overlapping images were registered to one another, the indivual images merged into a mosaic, and the overall process adjusted so that the mosaic was tied to the few ground control points available in this large sector. Two separate mosaics were used to span the whole sector.\r\n\r\nThe majority of the SAR data were acquired by the ERS-SAR instruments in August 1996, some ERS data were acquired in August 1993, and one Radarsat scene was acquired in September 1997. The data were pre-processed to produce a mosaic with a 100 m pixel size, and adjusted so that the majority of the coastline positions refer to the August 1996 epoch.\r\n\r\nThe location data are internally consistent, and extracted at nominally 200 m intervals. The external position accuracy is generally better than 600 m. The coverage is complete over the whole sector. The coordinate set includes some island/ice rise features. Two very large grounded icebergs are included.\r\n\r\nData are in an ascii arc/info export file format as geographic coordinates on the ITRF1996 system and contains attribute information.\r\n\r\nERS-SAR data, copyright ESA, 1993, 1996\r\n\r\nRadarsat data, copyright Canadian Space Agency, Agence spatiale canadienne, 1997.\r\n\r\nThis work was completed as part of ASAC projects 454, 1125 and 2224 (ASAC_454, ASAC_1125 and ASAC_2224).

本数据集涵盖东经79°至108°扇区内南极冰盖外缘的地理坐标，包含冰架、冰川及冰舌的边缘范围。本数据集通常不包含冰架或冰川内陆侧的接地带。

该冰缘边界通过对合成孔径雷达（Synthetic Aperture Radar，SAR）数据生成的影像镶嵌图开展解译确定。影像镶嵌图借助SAR影像配套的导航数据，将单幅影像转换至地图投影坐标系；通过配准重叠影像完成单幅影像的拼接，并针对该大型扇区内仅有的少量地面控制点对整体流程进行校准，最终完成整体镶嵌。本研究采用两幅独立的镶嵌图覆盖整个研究扇区。

多数合成孔径雷达数据由ERS-SAR传感器于1996年8月获取，部分ERS数据采集于1993年8月，另有1景Radarsat影像于1997年9月获取。所有数据经预处理生成像素分辨率为100米的镶嵌图，并经过校准以确保绝大多数海岸线点位对应1996年8月的观测时相。

本位置数据内部一致性优异，以名义间距200米的间隔提取得到；外部定位精度整体优于600米，研究扇区实现全范围覆盖。坐标集中包含部分岛屿/冰隆特征，同时纳入了两座大型接地冰山。

数据集采用ASCII Arc/Info导出文件格式存储，坐标系统为ITRF1996，附带属性信息。

ERS-SAR数据版权归欧洲空间局（ESA）所有，1993、1996年。

Radarsat数据版权归加拿大空间局（Agence spatiale canadienne）所有，1997年。

本研究作为ASAC项目454、1125及2224（ASAC_454、ASAC_1125及ASAC_2224）的一部分完成。