The great calving in 2017 did not have a significant impact on the Larsen C Ice Shelf in the short term

Abstract

The stability of the Larsen C Ice Shelf (LIS) has been widely studied due to its surface lowering, calving, and warming. In this study, we combined multisource remote-sensing data, calculated the long-term series of surface elevation above basal channels and basal melt rate, and analyzed the dynamic changes in the LIS before and after calving in 2017. We found that the basal channels were mainly concentrated in the southern LIS, and the basal melt rate was higher in the south. The Weddell Sea warm water mass entered the bottom of the LIS through the sea trough and promoted basal melting. There was an abnormal basal channel where changes in sea ice concentrations caused by wind-driven currents led to abnormal development. We did not observe significant changes in ice thickness, ice velocity and strain rate in the short term before and after the great calving in 2017. However, the basal melt rate was mainly influenced by the sea ice extent in front of the LIS from 2010 to 2020. Changes in the sea ice extent indirectly altered the proportion of High Salinity Shelf Water (HSSW) entering the ice shelf bottom water mass, which in turn promoted (or inhibited) basal melting of the LIS. In other words, we found no evidence for any dynamic changes in the LIS before and after the great calving in 2017. Since the calving area was within the Passive Shelf Ice (PSI), we have also provided additional evidence for the existence of the PSI. In addition, we speculate that the impact of calving on the LIS will not be visible in the short term, so we need to continuously observe the subsequent dynamic changes in the LIS.

Keywords

• Larsen-C Ice Shelf (LIS)
• 2017 calving event
• basal channel
• basal melt rate
• dynamic change