The following linked reference, and associated extracts, indicates that a new DoE (see also Replies #11, 12 & 13 regarding prior efforts from DoE labs) state-of-the-art Earth Systems Model, ESM, named Accelerated Climate Modeling for Energy (ACME), will include extensive sub-routines focused on the Antarctic Ice Sheet, AIS, (as well as the Greenland Ice Sheet, GIS) and possible abrupt SLR:
Bader D, W Collins, R Jacob, P Jones, P Rasch, M Taylor, P Thornton, and D Williams. "Accelerated Climate Modeling for Energy (ACME) Project Strategy and Initial Implementation Plan." 2014http://climatemodeling.science.energy.gov/sites/default/files/publications/acme-project-strategy-plan_0.pdf
Extract: "126.96.36.199 Cryosphere System
Could a dynamical instability in the Antarctic Ice Sheet be triggered within the next 40 years?
The objective is to examine the near-term risk of initiating the dynamic instability and onset of the collapse of the Antarctic Ice Sheet due to rapid melting by warming waters adjacent to the ice-sheet grounding lines. The experiment would be the first fully coupled global simulation to include dynamic ice shelf–ocean interactions for addressing the potential instability associated with grounding line dynamics in marine ice sheets around Antarctica. It will utilize several significant advances in the new ACME model, including the ability to enhance spatial resolution in both the ice sheet and ocean model to resolve grounding-line processes while still maintaining global extent in a coupled system and throughput for decadal simulations. The simulation will include an eddy-resolving Southern Ocean as well to better represent Circumpolar Deep Water (CDW) and dynamics associated with bringing this water onto the continental shelf under the ice sheet. Including the sea-ice model captures the process of buttressing at the ice shelf–sea-ice boundary. Finally, a fully coupled system is able to simulate changes in atmospheric forcing (e.g., poleward displacement of jets) that could influence the behavior of the Southern Ocean and sea ice.
The specific experiment will be a fully coupled simulation from 1970–2050 to explore whether rapid ice-sheet instability is triggered in this time frame. An ensemble would be desirable to address the likelihood of such an event, though this is not likely to be affordable in our configuration in this timeframe. The model configuration for this experiment will be a modified version of the standard high-resolution ACME configuration described below. The base configuration includes the atmosphere/land on a 0.25° cubed-sphere grid using the ACME-modified CAM5-SE atmosphere model. The subgrid orography modifications will be needed to resolve Antarctic surface mass balance at the ice-sheet margins. The ocean component will be MPAS-O on a Spherical Centroidal Voronoi Tesselations (SCVT) mesh with 15-km grid spacing at the equator, decreasing to 5 km in the Southern Ocean region. The default mesh will be extended southward to include critical Antarctic embayments and the resolution in these regions will be further enhanced if affordable. The vertical grid will be a hybrid coordinate with 100 vertical levels. The sea-ice component will be MPAS-CICE on the same ocean grid. Finally, we will add an Antarctic Ice Sheet model with resolution of 0.5–1 km near likely grounding-line locations and coarser resolution (~10 km) throughout the interior. For initial conditions, we will follow a similar spin-up procedure as with previous high-resolution simulations, with an ocean/ice state from an ocean/ice reanalysis-forced spin-up. For the ice sheet, an optimized initial condition should be available from the PISCEES project.
This first-of-its-kind coupled simulation will be focused largely on the ocean–ice shelf feedbacks and potential for dynamical instability and rapid SLR. It represents a first step toward a comprehensive SLR and impacts capability needed by the DOE to assess threats to coastal facilities. As work proceeds toward the more comprehensive experiments planned in the 10-year timeframe, we will be incrementally adding additional features. For example, work will begin under this project to develop an initial implementation of icebergs and primitive calving laws to capture the transport and distribution of ice and other material as the ice sheets flow into the ocean. Work also continues (as part of related projects) on a Greenland Ice Sheet model so that we can capture SLR contributions from both major ice sheets. We will also begin to include isostasy and ice-sheet self-gravity that can have a first-order effect on the regional SLR signature around the coastal U.S. We anticipate all of these effects to be included in a following ACME version. Further releases will begin to include wave models, further focusing of resolution in coastal and storm-track regions, and other capabilities needed to further refine SLR impact at regional scales.
188.8.131.52 Cryosphere System
How will regional variations in sea level rise interact with more extreme storms to enhance the coastal impacts of SLR?
The aim of this simulation is to determine the potential impacts on the nation’s coastal zones due to SLR exacerbated by regional variations in SLR and extreme storm surges. The novel aspects of this simulation are:
1. Fully coupled models of the cryosphere, including both major land ice sheets, the floating ice shelves surrounding Antarctica, the interactions with surrounding sea ice, and icebergs calved from Antarctica and Greenland
2. Complete treatments of the impacts of time-evolving isostasy and ice-sheet self-gravity on SLR
3. Addition of wave models to the ocean component
4. Deployment of enhanced resolution in all components to resolve dynamics at ice-sheet margins, sea-ice behavior, and the effects of severe weather on sea state in the major storm tracks
This experiment is based upon DOE’s advances in dynamic and adaptive ice-sheet modeling combined with the capacity for ultrahigh resolution of the land ice sheets and surrounding oceans using upcoming advances toward extreme-scale computing.
4.4 Ice Sheets
The ice-sheet model brings in a new set of interactions that must be understood and monitored for development or reduction of biases. The state of the atmosphere is essential to the surface mass balance, which in turn must be compared against other mass loss terms (iceberg calving, submarine melting). Along with monitoring of changes in grounded ice area and volume and these related mass balance terms, some of which may prove useful as metrics in a coupled context, a research problem we intend to take on is the development of Circumpolar Deep Water (CDW) metrics. Where waters are all near freezing, the relatively warm CDW, often found below colder and fresher waters, has a strong potential to accelerate submarine melting and therefore to strongly impact the overall mass balance of the Antarctic Ice Sheet. Stronger winds can drive greater upwelling and bring these warm waters in contact with the ice shelf. Research to understand the controls on CDW state and variability will be undertaken, facilitating the establishment of metrics focused on CDW mean state and variability, ensuring that transitions to or from rapid submarine melt states are not modeling artifacts but are robust and well understood. This effort will be critical for successfully answering the cryospheric driving question."
Extract: "We need a Great Climate Model.
The national laboratories of the Department of Energy are working on just such a model. Teamed with the National Center for Atmospheric Research, four academic institutions and one private company to form the Accelerated Climate Modeling for Energy, or ACME project, the national labs will help develop the most complete, fully coupled, state-of-the-science Earth system model to date.
Pacific Northwest National Laboratory (PNNL), Argonne, Brookhaven, Lawrence Berkeley, Lawrence Livermore, Los Alamos, Oak Ridge and Sandia will conduct simulations and modeling on the highest performance computing systems in the world. That includes over a hundred petaflop machines and the soon-to-be-operational exascale supercomputers."
Extract: "LOS ALAMOS, NM — With President Obama announcing climate-support initiatives at the 2014 United Nations Climate Summit, the U.S. Department of Energy national laboratories are teaming with academia and the private sector to develop the most advanced climate and Earth system computer model yet created. For Los Alamos National Laboratory researchers, it is a welcome advance for an already vibrant high-performance computing community.
Accelerated Climate Modeling for Energy, or ACME, is designed to accelerate the development and application of fully coupled, state-of-the-science Earth system models for scientific and energy applications."