An update on land-ice modeling in the CESM

• Main Author: Lipscomb, William H
• Language: unknown
• Published: 2021
• Subjects: 54 ENVIRONMENTAL SCIENCES; CLIMATE MODELS; CLIMATES; GLACIERS; GREENLAND; ICE CAPS; MASS BALANCE; SEA LEVEL; SIMULATION; Antarctic; Greenland; Antarc*; glacier; Ice Sheet
• Online Access: http://www.osti.gov/servlets/purl/1047150; https://www.osti.gov/biblio/1047150

Mass loss from land ice, including the Greenland and Antarctic ice sheets as well as smaller glacier and ice caps, is making a large and growing contribution to global sea-level rise. Land ice is only beginning to be incorporated in climate models. The goal of the Land Ice Working Group (LIWG) is to develop improved land-ice models and incorporate them in CESM, in order to provide useful, physically-based sea-level predictions. LJWG efforts to date have led to the inclusion of a dynamic ice-sheet model (the Glimmer Community Ice Sheet Model, or Glimmer-CISM) in the Community Earth System Model (CESM), which was released in June 2010. CESM also includes a new surface-mass-balance scheme for ice sheets in the Community Land Model. Initial modeling efforts are focused on the Greenland ice sheet. Preliminary results are promising. In particular, the simulated surface mass balance for Greenland is in good agreement with observations and regional model results. The current model, however, has significant limitations: The land-ice coupling is one-way; we are using a serial version of Glimmer-CISM with the shallow-ice approximation; and there is no ice-ocean coupling. During the next year we plan to implement two-way coupling (including ice-ocean coupling with a dynamic Antarctic ice sheet) with a parallel , higher-order version of Glimmer-CISM. We will also add parameterizations of small glaciers and ice caps. With these model improvements, CESM will be able to simulate all the major contributors to 21st century global sea-level rise. Results of the first round of simulations should be available in time to be included in the Fifth Assessment Report (ARS) of the Intergovernmental Panel on Climate Change.