Calving rate linearly dependent on sub-aerial terminus cliff height at tidewater glaciers around the Antarctic Peninsula

Abstract

Calving is the process of ice loss through the breaking of ice from a glacier’s terminus. Ice-flow models describe calving in various ways, although no consensus exists on the optimal approach. This is critical as the modelled calving rate can strongly influence projections of mass loss from glaciers and ice sheets. As the sub-aerial cliff height at a glacier’s ice front can be considered an indicator of the terminus stress regime, we used a wealth of high-resolution remote-sensing datasets to perform a detailed investigation into the observed relationship between the terminus cliff height and calving rate of 15 tidewater glaciers around the Antarctic Peninsula. The overall long-term response of the assessed glaciers revealed a linearly increasing relationship between calving rate and sub-aerial terminus cliff height from which we derived a calving parameterisation intended for implementation in long-term modelling of tidewater glaciers in the Antarctic Peninsula. Further, other existing calving parameterisations which are based on the terminus ice geometry yielded a poor fit to the assessed observational data. With the availability of such high-resolution data, better validation and constraint of calving parameterisations are now possible, which could greatly improve confidence in the implementation of calving and reliability of outputs from modelling studies.

Keywords

• Calving
• glacier monitoring
• glacier modelling