A fully coupled 3-D ice-sheet–sea-level model: algorithm and applications

Abstract

Abstract.Relative sea-level variations during the late Pleistocene can only be reconstructed with the knowledge of icesheet history. On the other hand, the knowledge of regional and global relative sea-level variations is necessary to learn about the changes in ice volume. Overcoming this problem of circularity demands a fully coupled system where ice sheets and sea level vary consistently in space and time and dynamically affect each other. Here we present results for the past 410 000 years (410 kyr) from the coupling of a set of 3-D ice-sheet-shelf models to a global sea-level model, which is based on the solution of the gravitationally selfconsistent sea-level equation. The sea-level model incorporates the glacial isostatic adjustment feedbacks for a Maxwell viscoelastic and rotating Earth model with coastal migration. Ice volume is computed with four 3-D ice-sheet-shelf models for North America, Eurasia, Greenland and Antarctica. Using an inverse approach, ice volume and temperature are derived from a benthic δ 18 O stacked record. The derived surface-air temperature anomaly is added to the present-day climatology to simulate glacial-interglacial changes in temperature and hence ice volume. The ice-sheet thickness variations are then forwarded to the sea-level model to compute the bedrock deformation, the change in sea-surface height and thus the relative sea-level change. The latter is then forwarded to the ice-sheet models. To quantify the impact of relative sea-level variations on ice-volume evolution, we have performed coupled and uncoupled simulations. The largest differences of ice-sheet thickness change occur at the edges of the ice sheets, where relative sea-level change significantly departs from the ocean-averaged sea-level variations.

Thermo-hydro-mechanical processes in fractured rock formations during a glacial advance

“…The pattern of fluid flow both within and at the base of a glacier can be a complex THM process by itself. Problems associated with the mechanics of glaciers (Weertman, 1972;Marshall, 2005), the motion of glaciers (Fowler, 1981(Fowler, , 2011Morland, 1987;Picasso et al, 2004;Gomez et al, 2013;Stucki and Schlunegger, 2013;Ahlkrona et al, 2013;Thoma et al, 2014), the constitutive properties of ice and ice-rock interfaces (Picasso et al, 2004;Marshall, 2005;Headley et al, 2012;Tezaur et al, 2015), the contact with the bedrock and the evolution of their shapes (dell'Isola and Hutter, 1998;Picasso et al, 2004;Dietrich et al, 2010;Headley et al, 2012;Nielsen et al, 2012;Pollard and deConto, 2012;Gomez et al, 2013;Stucki and Schlunegger, 2013;Steffen et al, 2006;de Boer et al, 2014) have been studied. The glacier dynamics on a centennial timescale due to climatic warming was studied by Hambrey et al (2005).…”

“…The longevity constraints with regard to the safety of deep geologic sequestration of high level radioactive waste suggest that the conventional scientific approaches to the investigations that involve laboratory and field studies must be complemented by approaches that will allow for predictions on timescales that are beyond conventional geological engineering activities involving underground facilities (Laughton et al, 1986;Chapman and McKinley, 1987;Selvadurai and Nguyen, 1997;Rutqvist et al, 2005;Alonso et al, 2005). Current concepts for deep geologic storage require an assessment of the geological setting containing a repository to account for geomorphological processes that can occur over timescales of several thousands of years.…”

Glacial Isostatic Adjustment modelling: historical perspectives, recent advances, and future directions

“…Subsequently, Gomez et al (2013) andde Boer et al (2014) and have used fully-coupled ice sheet-GIA models to produce ice-sheet reconstructions that are consistent with spatially-variable sea-level change over time. It is interesting to note that LGM reconstructions for Antarctica generated using coupled models tend to contain 1-2 m less ice (expressed as sea-level 555 equivalent) than reconstructions generated using uncoupled models (de Boer et al, 2017).…”

Progress in Numerical Modeling of Antarctic Ice-Sheet Dynamics

“…Such a sea-level fall reduces the ice flux at the grounding line by decreasing its ice thickness, hence stabilizing the ice sheet. Gravitationally self-consistent sea-level models incorporating Maxwell viscoelastic deformation of the solid Earth have recently been coupled to ice-sheet models to investigate their effect on millennial time scales [19,62] as its importance for the stability of the West-Antarctic ice sheet on these time scales has been demonstrated [74]. However, given the thin elastic lithosphere and low-viscosity upper mantle in West Antarctica, this effect may even be important on centennial time scales [63].…”