Called CICE, and pronounced "sea ice," the computer model has been the principal focus of Elizabeth Hunke's work at Los Alamos since she was first hired as a postdoctoral researcher in 1994. Working with Los Alamos staff members Bill Lipscomb and Phil Jones, Hunke and the CICE team have made the state-of-the-art model one of the most widely used tools for understanding the complex nature of sea ice. CICE is currently able to model various physical characteristics of sea ice at global resolutions of just less than one-half degree, or roughly 20 miles in the Polar Regions. In Arctic-only simulations, the ice has been modeled at resolutions as small as six miles. Hunke and her team are working at making these resolutions even finer.
Sea ice forms from seawater under arctic conditions. The ice moves around polar oceans in various states from thin, loosely amalgamated ice floes to thick, nearly solid ice sheets whose thickness is often increased by snow cover. Its presence in the oceans affects not only the ocean's salinity, since it leaves salt behind as the ice forms, but also the atmospheric conditions above the ice, where it affects chemical and heat exchanges between the two regimes.
According to Hunke, "Sea ice has quite a significant impact on global climate it usually covers an area of ocean larger than the United States and Canada combined. It also has a very high albedo, or reflectivity, and that much area reflects a significant amount of the sun's radiation, rather than allowing it to be absorbed by the ocean."
CICE was originally designed to be a component of global climate models and is a vital part of the Climate, Ocean and Sea Ice Modeling program at Los Alamos. Along with Los Alamos' powerful ocean model, the Parallel Ocean Program, CICE is a critical element of the Community Climate System Model, one of the world's leading general circulation climate models based at the National Center for Atmospheric Research (NCAR) in Boulder, Colo.
CICE has been used for a variety of global studies of climate, including variability of atmosphere and ocean processes, over time scales of decades to centuries. It has found use in regional climate studies where sea ice plays a major role, including studies of the Arctic and Southern oceans, North Atlantic and Baltic Sea. Researchers have used CICE in global carbon cycle studies, pale oceanographic studies and studies of sea ice physics and material properties.
Modeling groups around the world use CICE to make climate change predictions under various energy-use scenarios. The Intergovernmental Panel on Climate Change uses some of these predictions in its state-of-the-art climate assessments for policy makers. Whether used alone, or as a part of other larger modeling systems, CICE has been adopted by a number of institutions in the United States, including the National Centers for Environmental Prediction and NASA, along with at least 18 institutions in 10 countries.
The most recent release of the program allows CICE to run more efficiently on Japan's Earth Simulator supercomputer -- currently the world's fastest computer -- as part of NCAR's Community Climate System Model.
CICE has been funded by various sources over the years, but principal support has been from the Department of Energy's Climate Change Prediction Program.
Los Alamos National Laboratory is operated by the University of California for the National Nuclear Security Administration (NNSA) of the U.S. Department of Energy and works in partnership with NNSA's Sandia and Lawrence Livermore national laboratories to support NNSA in its mission.
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Photo credit: Los Alamos National Laboratory/LeRoy N. Sanchez
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Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns.