Abstract
Abstract. Polar ice sheets are important components of the Earth system. As the geometries of land, ocean and ice sheets evolve, they must be consistently captured within the lexicon of geodesy. Understanding the interplay between the processes such as ice-sheet dynamics, solid-Earth deformation, and sea-level adjustment requires both geodetically consistent and mass-conserving descriptions of evolving land and ocean domains, grounded ice sheets and floating ice shelves, and their respective interfaces. Here we present mathematical descriptions of a generic level set that can be used to track both the grounding lines and coastlines, in light of ice–ocean mass exchange and complex feedbacks from the solid Earth and sea level. We next present a unified method to accurately compute the sea-level contribution of evolving ice sheets based on the change in ice thickness, bedrock elevation and mean sea level caused by any geophysical processes. Our formalism can be applied to arbitrary geometries and at all timescales. While it can be used for applications with modeling, observations and the combination of two, it is best suited for Earth system models, comprising ice sheets, solid Earth and sea level, that seek to conserve mass.
Highlights
There has been intense interest in defining the physics involved in determining multidecadal change in the location and the migration rate of the grounding line, a boundary separating a grounded ice sheet from its floating extension, usually a floating ice shelf (e.g., Nowicki and Wingham, 2008; Schoof, 2012; Sergienko and Wingham, 2019)
Grounding lines are defined as the coastlines that belong to the ice domains
The set of generic, and quite simple, mathematical descriptions presented here can handle the complex geometries of both the coastlines and grounding lines, complementary to those of far-field land, ocean and ice domains and their respective overall evolutionary history. Based on this formalism of evolving coastlines and grounding lines, we present a unified method to calculate the exact fraction of ice thickness that contributes to the sealevel change over a given period
Summary
There has been intense interest in defining the physics involved in determining multidecadal change in the location and the migration rate of the grounding line, a boundary separating a grounded ice sheet from its floating extension, usually a floating ice shelf (e.g., Nowicki and Wingham, 2008; Schoof, 2012; Sergienko and Wingham, 2019). In the strict sense of the word, the change in global mean of MSL is given by the so-called barystatic sea-level change, which is the globalmean sea-level (GMSL) change due to the exchange of water between the land and the ocean, and the evolving spatial pattern of MSL is dictated by the GRD response of the solid Earth to land–ocean (water or sediment) mass exchange and the tectonic activities This definition of evolving MSL is familiar in GIA modeling wherein there is a requirement to solve for a gravitationally self-consistent solution of evolving bedrock and (nonsteric) MSL driven by the ice–ocean mass exchange following the Last Glacial Maximum (Farrell and Clark, 1976; Milne and Mitrovica, 1998). The MSL as defined above represents an equipotential surface whose spatial pattern matches the geoid (Tamisiea, 2011)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
