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Analysis of Tidal Deflection and Ice Properties of Ross Ice Shelf, Antarctica, by using DDInSAR Imagery

DDInSAR 영상을 이용한 남극 로스 빙붕의 조위변형과 물성 분석

  • Han, Soojeong (Department of Geophysics, Kangwon National University) ;
  • Han, Hyangsun (Unit of Arctic Sea-Ice Prediction, Korea Polar Research Institute) ;
  • Lee, Hoonyol (Department of Geophysics, Kangwon National University)
  • 한수정 (강원대학교 지구물리학과) ;
  • 한향선 (극지연구소 북극해빙예측사업단) ;
  • 이훈열 (강원대학교 지구물리학과)
  • Received : 2019.11.18
  • Accepted : 2019.12.05
  • Published : 2019.12.31

Abstract

This study analyzes the tide deformation of land boundary regions on the east (Region A) and west (Region B) sides of the Ross Ice Shelf in Antarctica using Double-Differential Interferometric Synthetic Aperture Radar (DDInSAR). A total of seven Sentinel-1A SAR images acquired in 2015-2016 were used to estimate the accuracy of tide prediction model and Young's modulus of ice shelf. First, we compared the Ross Sea Height-based Tidal Inverse (Ross_Inv) model, which is a representative tide prediction model for the Antarctic Ross Sea, with the tide deformation of the ice shelf extracted from the DDInSAR image. The accuracy was analyzed as 3.86 cm in the east region of Ross Ice Shelf and it was confirmed that the inverse barometric pressure effect must be corrected in the tide model. However, in the east, it is confirmed that the tide model may be inaccurate because a large error occurs even after correction of the atmospheric effect. In addition, the Young's modulus of the ice was calculated on the basis of the one-dimensional elastic beam model showing the correlation between the width of the hinge zone where the tide strain occurs and the ice thickness. For this purpose, the grounding line is defined as the line where the displacement caused by the tide appears in the DDInSAR image, and the hinge line is defined as the line to have the local maximum/minimum deformation, and the hinge zone as the area between the two lines. According to the one-dimensional elastic beam model assuming a semi-infinite plane, the width of the hinge region is directly proportional to the 0.75 power of the ice thickness. The width of the hinge zone was measured in the area where the ground line and the hinge line were close to the straight line shown in DDInSAR. The linear regression analysis with the 0.75 power of BEDMAP2 ice thickness estimated the Young's modulus of 1.77±0.73 GPa in the east and west of the Ross Ice Shelf. In this way, more accurate Young's modulus can be estimated by accumulating Sentinel-1 images in the future.

Acknowledgement

Supported by : 한국연구재단

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