2. What is the “Grounding Line”?

Fig. 1 below is a diagrammatic sketch of the grounding line and coastline. The grounding line lies on the boundary of the Antarctic ice sheet adjoining the land base terrain and the sea ice shelves surrounding the ice sheet. The sea ice shelf area floats on the ocean and oscillates vertically due to ocean tides, whilst the Antarctic ice sheet can be considered static over the short term (one to several days). InSAR image, vertical movements of the ice shelf caused by ocean tides appear as a dense fringe pattern at the boundary with the static ice sheet, caused by changes in the vertical distance of the ice shelf from the satellite as shown by, e.g., Goldstein et al.⁵⁾. The grounding line can be extracted by manually digitizing the inland boundary of the dense fringe area (approximately 1 km wide).

Fig.1 Schematic Figure of grounding line