Physically consistent eddy-resolving state estimation and prediction of the coupled pan-Arctic climate system at daily to interannual time scales using the Regional Arctic Climate Model (RACM)

Collaborative Research Statement:

Collaborative Project between the Naval Postgraduate School (W. Maslowski – PI, A. Rob- erts, J. Clement Kinney) and University of Colorado at Boulder (J. Cassano and M. Hughes).

The proposed research leverages ongoing developments of the state-of-the-art Regional Arctic Climate Model (RACM) through a multi-institutional program supported by the Department of Energy Regional and Global Climate Modeling (DOE/RGCM) program and two ongoing complementary projects. This new project is aimed at improved modeling of the atmosphere-ice-ocean interface in the presence of tides and eddies to advance representation of the past and present state of the Arctic Climate System and prediction of its future states at time scales from daily (operational) through seasonal, interannual, and up to decadal (tactical).

Science Objectives:

The overall science goal of this project is to address the short to long-term US Navy / DOD (Arctic Roadmap, 2009) and national requirements (Roberts et al., 2010) to un derstand and predict arctic climate change. Three main objectives are to (i) advance understanding and model representation of critical physical processes and feedbacks of importance to sea ice thickness and area distribution using a combination of forward modeling and state estimation techniques and (ii) investigate the relation between the upper-ocean heat content and sea ice volume change and its potential feedback in amplifying ice melt and (iii) upgrade RACM with the above improvements to advance both operational and tactical prediction of arctic climate using a single model.

Hypothesis - We hypothesize that the oceanic heat flux convergence in the upper Arctic Ocean is one of the main, yet overlooked, driving forces acting to reduce the sea ice cover:

In addition to the atmospheric forcing at the surface, the accumulation and distribution of oceanic heat below the mixed layer and above the halocline coupled to the upper-ocean dynamics can modulate the ice edge position and state of sea ice cover and determine regions of net growth/melt of sea ice and variability in multi-year and first-year ice distribution. The removal of sea ice for prolonged periods of time acts to increase oceanic heat content in the upper ocean, which reduces ice growth during winter and accelerates sea ice melt in early spring and onwards the following year. Realistic model representation of mesoscale ocean dynamics and air-sea feedback processes under diminishing sea ice cover are critical to test this hypothesis.

Benefits and Outcomes:

Given the continued warming and summer sea ice cover decrease in the Arctic during the past decades, this proposal will allow a better understanding and planning of current and future operational needs in support of the continued US commercial and tactical interests in the region. It will also have broader impacts by facilitating studies of the potential increased exploration of natural resources and of the use of northern sea routes from the Pacific Ocean to Europe. Such activities will change the strategic importance of the pan-Arctic region.


Training and Outreach:

The project will involve graduate and postdoctoral education in research. The postdoctoral and graduate students will receive practical training in data assimilation, climate prediction and synthesis of model output and observational data. All PIs will present results of this research in classes, at scientific meetings, through a project-dedicated web site and in peer-reviewed literature.