Bulletin of Surveying and Mapping ›› 2023, Vol. 0 ›› Issue (9): 70-76.doi: 10.13474/j.cnki.11-2246.2023.0267

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Application and analysis of Sentinel-1 images in Antarctic grounding line extraction

ZHAO Xianren, XING Zhe, ZHANG Feng, GUO Canwen, WANG Jing, SUN Yi, MA Yong, ZHAO Binru, WANG Jian   

  1. National Marine Data and Information Service, Tianjin 300171, China
  • Received:2022-12-06 Published:2023-10-08

Abstract: The grounding line is the boundary between the inland grounded ice sheet and the floating ice shelf. Precise extraction of the grounding line has a great significance for the calculation of the material balance of Antarctic glaciers, the modeling of glacier dynamics, glacier changes and sea level changes. This paper aims at the application characteristics of Sentinel-1A/B radar image data in the large-scale extraction of Antarctic grounding line. Based on the Sentinel-1A/B radar image data in 2020 and the DDInSAR method, a large-scale extraction of the Antarctic grounding line is carried out.The grounding line is about 23 472 km.Combined with MEaSURE_GL, MOA_ Gl2009,MEaSUREs velocity and other data,we have comprehensive analyzed the grounding line extraction result.The result shows that using Sentinel-1A/B radar image data and DDInSAR method can realize long-term, efficient and comprehensive extraction of Antarctic grounding line.The grounding line in different regions of Antarctica has different changing characteristics, including stability, retreat, advance, disappearance and ice rise.In the Antarctic Peninsula and the West Antarctic, we can use the 6 d Sentinel-1A/B radar image data to extract the grounding line. In the large part of the Eest Antarctic,we can only use the 12 d Sentinel-1A/B radar image data to extract the grounding line.The strength of tidal motion affects the quality of the grounding line extraction, the grounding line extraction quality is higher in the strong tidal area of the West Antarctic, and the grounding line extraction quality in the weak tidal area around the East Antarctic ice sheet is poor or the result is vacant.The extraction of the Antarctic grounding line is greatly affected by the ice velocity, when the ice velocity exceeds 400 m/a, the extraction quality of the grounding line is poor or even unable to extract due to the existence of the large ice velocity.When using Sentinel-1A/B radar image data to extract the Antarctic grounding line, the image data of the Antarctic Peninsula and the East Antarctic are preferentially selected during the autumn period, and the image data of the West Antarctic during the summer period are preferentially selected.

Key words: grounding line, DDInSAR, Antarctic, Sentinel-1A/B, ice velocity, tidal motion

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