A sea ice modeling workshop was convened on 3-4 February 2016 in Boulder, CO for the purpose of informing NOAA on the inclusion and selection of a community-contributed sea ice model into the future Next-Generation Global Prediction System (NGGPS). Another workshop goal was to identify potential research and development opportunities and gaps.
The workshop was hosted at the National Center for Atmospheric Research (NCAR) by the DTC’s Global Model Test Bed, and counted as sponsors the National Weather Service, the NOAA Office of Atmospheric Research Climate Program Office, and the Office of Naval Research. Sixty-five scientists attended the workshop, representing a broad spectrum of research and operational organizations, such as universities, NOAA, Navy, Department of Energy (DoE), the US National Ice Center, National Snow and Ice Data Center, NCAR, NASA, and DTC. International participation included representatives from the UK Meteorological Office, U. Reading, U. Toronto, and Environment Canada.
NOAA’s NGGPS will be a single fully coupled Earth modeling system with application to forecasts from days to seasons, spanning spatial scales from 1 to 25 km. While the sea ice model to be selected for inclusion in NGGPS needs to have good performance for all forecast applications over these time and space scales, this workshop focused on the short- and medium-term sea ice forecast needs. Workshop participants reviewed several state-of-the-art sea ice modeling efforts, along with various Earth modeling systems, such as the NCEP Keeping Ice’S Simplicity (KISS) model, the DoE Community Ice CodE (CICE) model, the NOAA Geophysical Fluid Dynamics Laboratory Sea Ice Simulator (SIS), the NOAA National Centers for Environmental Prediction Climate Forecast System (CFS), the Canadian Regional Ice-Ocean Prediction System (RIOPS), the ESRL Regional Arctic System Model (RASM) and the Navy Research Laboratory Arctic Cap Nowcast/Forecast System (ACNFS).
It was noted that the majority of advanced sea ice models have similar physical parameterizations, and that the differences among advanced models is smaller than the uncertainty due to initial conditions and external forcing. Given that the use of a community-contributed and supported model in NGGPS was raised as a priority for model selection, participants recommended the tentative adoption of the CICE model, pending follow-up testing and addressing concerns raised regarding the CICE model governance and potential for introduction of numerical artifacts due to differences in staggering between the grids used in the ocean models and in CICE.
The framework for follow-up testing was discussed and important points regarding resolution, domain, coupling, verification metrics, and observations were raised. The importance of the ocean model for ice model performance was also discussed, and will need to be a factor in the test design. These issues will be considered by a tiger team formed to design and conduct the tests. A variety of synergistic project efforts in the scientific community were identified and recommendations for future model development were put forth. Test results will be used to prioritize future model development efforts.
For more information on the NGGPS sea ice modeling workshop and its presentations, please visit http://www.dtcenter.org/events/workshops16/seaice