*Glacial Isostatic Model*

The ultimate isostatic compensation achieved by any harmonic component is given by [44,55]:

$$h(k) = \frac{F(k)\alpha^{-1}}{\rho \mathcal{G}} \tag{A1}$$

where F(k) = transformed ice load, ρ = density of the upper mantle, and g = gravity.

The 'lithosphere filter' is α = <sup>2</sup>μ*k* ρ*g* S2 − k2H2 + (CS + kH)]/(S + kHC), where k = wavenumber, H = elastic thickness of the lithosphere, μ = Lame's parameter, S = sinh kH and C = cosh kH. The relation between the flexural rigidity (D) and the elastic thickness of the lithosphere (H) is given by the equation *D* = *EH*<sup>3</sup> <sup>12</sup>(<sup>1</sup>−ν<sup>2</sup>), where E = Young's modulus and ν = Poisson's ratio.
