Collaborative Research: Towards Advanced Understanding and Improved Decadal/Centennial Prediction of Arctic Sea Ice State and Climate Change

Arctic sea ice is a sensitive indicator of the state of Arctic climate and its polar amplification. However, the causes of Arctic ice melt and its rate are not fully understood. Global climate models (GCMs) vary widely in their predictions of warming and the rate of Arctic ice melt, suggesting it may take anywhere from a couple of decades to more than a century to melt most of the summer sea ice cover. The multi- model average forecast based on results from the Intergovernmental Panel for Climate Change Fourth Assessment Report (IPCC-AR4) predicts a 50% reduction of summer sea ice in the Arctic Ocean by the end of this century. Unfortunately, the majority of those models have significant limitations in their representation of past and present sea ice variability in the Arctic. Some of the critical limitations include: sea ice thickness distribution, deformation, variability and export, air-ice-sea interactions, northward oceanic/atmospheric heat convergence, and freshwater export. This proposal intends to target potential causes of those limitations associated with resolution and sophistication of ocean-atmosphere boundary layers and their interaction with and without the sea ice cover. The recently developed high-resolution Regional Arctic Climate system Model (RACM) will be used as a tool for numerical simulation and synthesis with in-situ and satellite observations to investigate the critical physical feedback processes and interactions between the atmosphere, ocean, and land under a diminishing sea ice cover.

Intellectual Merit
The overarching goal of the project is to advance understanding of Arctic climate system operation and variability to improve model prediction of Arctic climate change at decadal to centennial scales. A set of specific objectives is proposed centered on the following main science hypothesis:
Given the projections of continued global warming and its northern high-latitude amplification, the Arctic will become nearly ice-free during summer in the near future, resulting in altered physical state of and interconnections within the Arctic climate system.
To confirm or disprove the above hypothesis, our approach is to use subsets of model components and fully coupled RACM to address the following specific objectives:
- Identify potential improvements in the simulated sea ice thickness distribution and deformation due to increasing model resolution and representation of fine-scale ice-ocean interactions
- Investigate effects of shrinking and thinning sea ice on ice kinematics and its consequences on changing air-ice and ice-ocean interactions
- Examine and quantify consequences of melting sea ice on the increased upper ocean heat content and its potential for increased ice melt due to a positive ice-ocean feedback loop
- Assess the influence of excess oceanic heat release, especially in fall and winter, on potentially enhancing cyclonic tendency in the atmosphere
- Explore the importance of increased sea ice melt and runoff to the Arctic hydrological cycle and its acceleration in the context of first-year ice growth and survival
- Integrate positive and negative feedback processes into model simulations of warming climate scenario to determine their net impact on the long-term state of Arctic ice cover
- Identify physical and numerical requirements of future GCMs to significantly improve model skill in representing past and present and in predicting future Arctic climate change.
A hierarchy of well designed one-way and fully coupled regional climate system model experiments will focus on the above objectives. Such experiments will provide advanced insight into the behavior of the Arctic climate system that is not currently attainable using either individual regional component models or GCMs.

Education, Outreach and Broader Impacts
We will develop an immersive Arctic Ocean Modeling exhibit for the University of Alaska Museum of the North (UAMN) as a core component of our education and outreach activities. The proposed 5-7 minute presentation will be made available to a network of science museums across the United States via an online Magic Planet community. In addition, the University of Colorado co-PIs will seek to engage undergraduate students in RACM research activities at no cost to this project, through University of Colorado Summer Multicultural Access to Research Training (SMART) program for undergraduates, and the UCAR Significant Opportunities in Atmospheric Research and Science (SOARS) program. This work will involve undergraduate and graduate education and will provide basic training in coupled climate system modeling and analysis of the resulting model output. All PIs will present results of this research in classes, seminars, scientific meetings and peer-reviewed publications.
The proposed project helps to lay the foundation for a community regional Arctic System Model as recommended in the recently published report to NSF. This research will also address or facilitate other studies related to potential implications of Arctic sea ice melt and warming climate, including consequences for the global ocean thermohaline circulation, Greenland ice sheet, ecosystem, shipping, natural resource development, policymaking and defense. Output from the baseline simulations will be made available to the community through either the ARCSS Data Coordination Center or a Live Access Server at the Naval Postgraduate School, to be developed in support of this project.


Participant List

Investigators:

Wieslaw Maslowski, Naval Postgraduate School (PI): Principal investigator and scientific oversight.

Andrew Roberts, Naval Postgraduate School (Co-PI): Primary responsibility for implementation of embedded sea ice, ice-ocean simulation and model evaluation in the Regional Arctic System Model.

John Cassano, University of Colorado Boulder (Co-PI): Investigation of atmospheric feedbacks and responses to changes in the ice-ocean boundary layer and coupling methods in the Regional Arctic System Model.

Collaborators:

Matthew Hecht and Elizabeth Hunke, Los Alamos National Laboratory: Collaboration on the introduction of z* coordinates to RASM and sea ice “embedding” of the sea ice model (CICE) into the ocean model (POP).

Ron Kwok, NASA Jet Propulsion Laboratory: Collaboration on the use of Radarsat Geophysical Processor System (RGPS) sea ice kinematic data for model evaluation

Deniel Feltham, Centre for Polar Observation and Modelling, University College London: Collaboration on testing a high resolution sea ice diamond rheology created at University College London for use in CICE.

Robert Osinski, Poland Institute of Oceanology: Collaboration on simulating sea ice at eddy resolving resolution in RASM.

Jennifer Hutchings, University of Alaska Fairbanks: Collaboration on the use of International Arctic Buoy Program data for model evaluation

Student participants:

Mark Murnane, Naval Postgraduate School Masters Student: Completed a masters thesis evaluating the shear characteristics of recent simulations of the Regional Arctic Systme Model.

Thomas Mills, Naval Postgraduate School Masters Student: Currently undertaking masters-level research to evaluate instances of coincident sea ice shear and oceanic upwelling at semi-diurnal frequencies in the Regional Arctic System Model.