A Systematic Study of the Fracturing of Ronne - Filchner Ice Shelf, Antarctica, Using Multisource Satellite Data from 2001 to 2016

Abstract

Abstract. We propose a new framework of systematic fracture mapping and major calving event prediction for the large ice shelves in Antarctica using multisource satellite data, including optical imagery, SAR imagery, altimetric data, and stereo mapping imagery. The new framework is implemented and 10 applied for a comprehensive study of the fracturing of Ronne-Filchner Ice Shelf (RFIS), the second largest ice shelf in Antarctica, using a long time dataset dating back to 1957. New remote sensing data that have been made available in the past decade, including Landsat 8, WV-2, ZY-3 and others, greatly enhance our abilities to detect new fractures and monitor large rifts in three dimensions. Two large rifts, Rifts 1 and 2, were newly detected and are comparable to the Grand Chasm that caused a major calving event in 15 the region in 1986. Three-dimensional rift models generated from quasi real-time stereo ZY-3 images revealed important topographic information about the large rifts that can be used to improve the reliability of ice shelf modeling and support enhanced analyses of ice shelf stability. Based on the results of the 2D and 3D fracture mapping, the spatial and temporal analyses of the overall fracture changes and large rift evolutions, i.e., the level of fracturing in RFIS, were slightly increased, particularly at the front of the ice 20 sheet. The overall fracture observations do not seem to suggest immediate significant impacts on the stability of the shelf. However, the most active regional fracturing activities occurred at the front of Filchner Ice Shelf (FIS). A potential upcoming major calving event of FIS is estimated to occur in 2051.The stability of the ice shelf, particularly with regard to the developments of Rifts 1 and 2, should be closely monitored.

Tidal influences on a future evolution of the Filchner–Ronne Ice Shelf cavity in the Weddell Sea, Antarctica

“…The extent of freezing conditions is important because marine ice accretion supports ice shelf stability through its effect on the mechanical properties of ice (Kulessa et al, 2014;McGrath et al, 2014;Li et al, 2017) and by altering the extent of grounding on topographic highs such as ice rises and rumples. Our standard cold tide-forced case produces local maxima in marine ice growth rates in the northwestern RIS, the region northeast and east of Korff Ice Rise, and the region to the north and west of Henry Ice Rise (Fig.…”

A Bidirectional Analysis Method for Extracting Glacier Crevasses from Airborne LiDAR Point Clouds

“…Liu et al [12] detected sparse crevasse points from three-dimensional ICESat-1/GLAS footprints for large-size crevasses. Other researchers reconstructed three-dimensional information of glacier surfaces using stereophotogrammetry [14][15][16][17], and three-dimensional crevasses can also be captured [18,19]. Although these stereophotogrammetry methods are efficient for the three-dimensional mapping of crevasses, they are still limited by three factors: (1) The difficulty of surveying evenly distributed ground control points; (2) the low contrast of the texture over a glacier surface; and (3) the lack of light at the bottom and sidewalls of a crevasse.…”

Response to comments by Dr. Hartmut Hellmer

“…Studies of Larsen C Ice Shelf (Mueller et al, 2012) and Pine Island Glacier ice shelf (Schodlok et al, 2012) showed that changes to the ice shelf cavity shape can significantly alter the spatial pattern of basal melt rate, particularly in regions where tidal currents contribute substantially to the total turbulent kinetic energy near the ice base. Tides were not explicitly included in the forcing for the Hellmer et al (2012) study; however, tidal currents often play a critical role in setting the pattern and magnitude of basal melt rates under cold water ice shelves (MacAyeal, 1984;Padman et al, 2018) including FRIS (Makinson et al, 2011), which leads us to hypothesize that tides would influence changes in meltwater production from a warming ocean.…”