Cooperative Institute for Research in Environmental Sciences

A case study of high frequency ice-ocean-atmosphere dynamic coupling in the Regional Arctic System Model.

A. Roberts, J. Cassano, A. DuVivier, M. Hughes, W. Maslowski, R. Osinski, A. Craig, and B. Nijssen

2014, Annals of Glaciology, in press

We demonstrate the high-frequency sea ice mechanics capability of the Regional Arctic System Model (RASM) in a year-long case study predating the rapid recent decline in perennial arctic sea ice. RASM is a high resolution fully coupled pan-Arctic climate model that uses the same ocean, sea ice and coupling infrastructure as the Community Earth System Model (CESM), and is configured at an eddy-permitting resolution of 1/12° for the ice-ocean and 50 km for the atmosphere-land model components. All RASM components are coupled at super-inertial 20-minute intervals. We demonstrate the ability of RASM to replicate observed 1.5-2.5 per day drift in the Arctic using rotary wavelet methods. These methods allow us to generate basin-wide statistics and maps of inertial oscillations, pointing to likely enhanced oceanic mixing and a close relationship between cyclonic activity in the Arctic and inertial oscillations during the case study year, irrespective of the strength of the sea ice pack. We conclude that the same coupling mechanisms applied to CESM as in RASM will enable realistic simulation of inertial oscillation for use in a global investigation, enabling investigation of the climatic relationship between high-frequency sea ice mechanics, oceanic mixing and storm tracks in both the Arctic and Antarctic.