Simulating interactive ice sheets in the multi-resolution AWI-ESM 1.2: A case study using SCOPE 1.0

Abstract

Abstract. Interactions between the climate and the cryosphere have the potential to induce strong non-linear transitions in the Earth's climate. These interactions influence both the atmospheric circulation, by changing the ice sheet's geometry, as well as the oceanic circulation, by modification of the water mass properties. Furthermore, the waxing and waning of large continental ice sheets influences the global albedo, altering the energy balance of the Earth System and inducing climate-ice sheet feedbacks on a global scale as evident in Pleistocene glacial-interglacial cycles. To date, few fully comprehensive models exist, that do not only contain a coupled atmosphere/land/ocean component, but also consider interactive cryosphere physics. Yet, on glacial-interglacial and tectonic time scales, as well as in the Anthropocene, ice sheets are not in equilibrium with the climate, and prescribed fixed ice sheet representations in the model can principally be only an approximation to reality. Only climate models, that contain interactive ice sheets, can produce simulations of the Earth's climate which include all feedbacks and processes related to atmosphere-land-ocean-ice interactions. Previous fully coupled models were limited either by low spatial resolution or an incomplete representation of ice sheet processes, such as iceberg calving, surface ablation processes, and ocean/ice-shelf interactions. Here, we present the newly developed AWI-Earth System Model (AWI-ESM), which tackles some of these problems. Our modelling toolbox is based on the AWI-climate model, including atmosphere and vegetation components suitable for paleoclimate studies, a multi-resolution global ocean component which can be refined to simulate regions of interest at high resolution, and an ice sheet component suitable for simulating both ice sheet and ice shelf dynamics and thermodynamics. We describe the currently implemented coupling between these components, present first results for the Mid-Holocene and Last Interglacial, and introduce further ideas for scientific applications for both future and past climate states with a focus on the Northern Hemisphere. Finally, we provide an outlook on the potential of such fully coupled Earth System models in improving representation of climate-ice sheet feedbacks in future paleoclimate studies with this model.

The diurnal Energy Balance Model (dEBM): a convenient surface mass balance solution for ice sheets in Earth system modeling

“…As a natural next step we intend to test the dEBM in the framework of the coupled AWI-ESM Earth system model (Gierz et al, 2020) to study glacial-interglacial timescales. Furthermore, dEBM can be used as a diagnostic for climate simulations based on fixed ice sheet geometries or coupled to an ice sheet model using forcing derived from climate models and observation as in Niu et al (2019).…”

“…Here we refine the approach of Krebs-Kanzow et al (2018b) and present a novel stand-alone SMB model, dEBM. The presented model is efficient on millennial timescales and particularly suitable for Earth system modeling on long timescales in a modular framework such as Gierz et al (2020), as it only requires monthly forcing. The scheme now also includes an albedo scheme, accounts for changes in atmospheric composition and statistically resolves submonthly variability in cloud cover.…”

AMOC Recovery in a Multicentennial Scenario Using a Coupled Atmosphere‐Ocean‐Ice Sheet Model

“…Code for the AWI‐ESM‐PISM coupler SCOPE is available under https://gitlab.awi.de/pgierz/scope (Gierz et al, 2020) and can also be installed via the Python package managing system, pip, via the command pip install scope‐coupler. SCOPE is a free software, licensed under the GNU Public License, v.3.…”

PARASO, a circum-Antarctic fully-coupled ice-sheet - ocean - sea-ice - atmosphere - land model involving f.ETISh1.7, NEMO3.6, LIM3.6, COSMO5.0 and CLM4.5

“…Coupled ocean -ice-sheet configurations, with dynamical AIS geometry, have also been developed: using global climate models of intermediate complexity (Swingedouw et al, 2008;Goelzer et al, 2016;Ganopolski and Brovkin, 2017), but also state-of-the-art ocean models over local domains (Seroussi et al, 2017;Timmermann and Goeller, 2017), and even at the global scale, for pluri-centennial simulations relying on parameterized ice-shelf cavity circulation (Kreuzer et al, 2020). Model configurations including ice-sheet coupling, with cavities explicitly resolved, are currently under development in a few global Earth system models (Golaz et al, 2019;Sellar et al, 2019;Gierz et al, 2020), as well as in more idealized settings for performing sensitivity studies (Richter et al, 2021).…”