Rift Assessment and Potential Calving Zone of Amery Ice Shelf, East Antarctica

Abstract

Ice shelves line the peripheries of Antarctica. Rift and crevasses are two main deformational structures affecting ice shelf stability. The present study deals with propagation-widening of five active rifts and future potential calving zones on Amery Ice Shelf (AIS), East Antarctica, between 2000 and 2017 using moderate resolution image spectroradiometer (MODIS) data. The widening and rift propagating rate, as well as advancement in AIS show abnormal behaviour. The expansion of AIS differs across the shelf. The highest rate of advancement was observed in 2012-2013 (~517 sq. km) and the lowest was observed in 2000-2001 (~35 sq. km). The rift system shows variability in its proportion and having poor relationship with environmental processes, which suggests heterogeneities in the AIS. The abnormal behaviour of rift propagation during the study period can be attributed to tsunamis, tide, current action, crevasses pattern and icequakes in the vicinity of the study region.

Understanding of an Iceberg Breaking Off Event Based on Ice-Front Motion Analysis of Amery Ice Shelf, Antarctica

“…This observation agrees with the previous estimates [6,8]. In addition, the highest advancement of the AIS calving front was observed in 2012-2015 from 2000 to 2017, which agrees with Darji et al's observation in 2012-2013 [10]. However, the advance of the central portion of the AIS calving front accelerated relative to its eastern and western portions.…”

“…Walker et al observed that the AIS calving front had steadily readvanced seaward in the following 50 years after its last major calving event that occurred in the early 1960s [7,9]. Darji et al also examined the advancement rate of the AIS calving front but presented it in the areal changes per year, where the highest advancement rate at ~517 km 2 yr −1 was observed in 2012-2013 between 2000 and 2017 [10].…”

“…This rift system, illustrated in Figure 1, consists of two longitudinal-to-flow rifts (A0 and B) and two transverse-to-flow rifts (A1 and A2), where rifts A0, A1, and A2 comprise rift A of Fricker et al [11]. Darji et al estimated the propagation rates of rift A and rift B at 0.19 km yr −1 and 0.03 km yr −1 , respectively, from 2000 to 2017 [10]. In addition, Darji et al observed the propagation rates of rift A1 and rift A2 at 1.43 km yr −1 and 0.84 km yr −1 , respectively, during the same study period [10].…”

“…Darji et al estimated the propagation rates of rift A and rift B at 0.19 km yr −1 and 0.03 km yr −1 , respectively, from 2000 to 2017 [10]. In addition, Darji et al observed the propagation rates of rift A1 and rift A2 at 1.43 km yr −1 and 0.84 km yr −1 , respectively, during the same study period [10]. Zhao et al reported the rapid propagations of the rift A1 and the rift A2 at the speed of 4.49 m d −1 (equivalent to 1.64 km yr −1 ) and 2.53 m d −1 (equivalent to 0.92 km yr −1 ) from 2004 to 2012, respectively [12].…”

Atmospheric extremes caused high oceanward sea surface slope triggering the biggest calving event in more than 50 years at the Amery Ice Shelf

“…Sentinel-1 data have been used to determine potential surface melt (e.g., Datta et al, 2019) and to track ice velocity over the Amery Ice Shelf prior to the D28 iceberg calving by using feature tracking in ESA's SNAP (Sentinel Application Platform) Sentinel-1 toolbox. Sentinel-3A and Sentinel-3B data were used via the ESA Ocean Virtual Laboratory application to determine the wave height at the front of the Amery Ice Shelf.…”