Earlier large-scale ice sheet experiments e.g. those run during ice2sea and SeaRISE initiatives have shown that ice sheet initialization can have a large effect on sea-level projections and gives rise to important uncertainties. Improving initialization techniques is currently a field of active research, which makes it difficult to prescribe one technique as the method of choice for ISMIP6. Our goal is therefore to compare and evaluate the initialization methods used in the ice sheet modeling community and estimate uncertainty associated with initialization.
Instead, we first propose a “Come as you are”- approach, which allows participants to contribute with their currently used model setup and initialization technique for intercomparison ( initMIP ). We hope this allows getting modelers involved early in the ISMIP6 process and keeps the workload for participants as low as possible. Furthermore, the proposed schematic experiments may facilitate to document on-going model development. Starting early in the CMIP6 process implies relying on schematic forcing for the initiation experiments that is independent from CMIP6 AOGCM output, which will only become available later on.
The initMIP is the first in a series of ISMIP6 ice sheet model intercomparison activities and comprises two separate projects for the Greenland and Antarctic ice sheets:
As described in the main ISMIP6 page, the primary goal of ISMIP6 is to improve projections of sea level rise via projections of the evolution of the Greenland and Antarctic ice sheets under a changing climate, along with a quantification of associated uncertainties (associated with both uncertainty in climate forcing and in the response of the ice sheets).
The standalone ISMIP6 ice sheet experiments are therefore tightly linked with the CMIP6 past and future climate simulation from any AOGCM, and meant to complement the coupled ice sheet-climate simulation.
In addition to the current initializations (initMIP) as mentioned above, ISMIP6 delivered future sea level projections from dynamic ice sheet models:
The ISMIP6 flow is shown in the diagram below:
The table below illustrates the many possible ways that Atmospheric Forcings can be provided to an ice sheet model.
Please fill free to indicate other methods!
The table below illustrates the many possible ways that Oceanic Forcings can be provided to an ice sheet model.
Please fill free to indicate new methods!