A New Approach for Modelling Post-Glacial Sea Level

Abstract:

We present a new method for modelling gravitationally self-consistent
sea level change in response to the growth and decay of ice sheets. Traditionally,
this problem is solved iteratively using the so-called “sea level equation”.
While this approach is ef‚fective, its implementation in laterally heterogeneous
earth models is costly due to its iterative nature. It is, furthermore,
poorly suited to the application of adjoint methods to the inverse sea level
problem. Our approach is based upon a time-domain rate-formulation of
the viscoelastic loading problem, which we here extend to incorporate gravitationally
self-consistent sea level change including the e‚ffects of shoreline
migration. ŒThis results in a coupled set of quasi-linear evolutions equations
for the problem that can be numerically integrated without recourse iterative
methods. Based on this new rate-formulation, we also describe the fi€rst
application of adjoint methods to the inverse sea level problem.