The atmospheric environment service regional ice model (RIM) for operational applications

Abstract

This paper describes the development of and simulations with a regional scale sea ice dynamics model for obtaining short‐range, real‐time or near real‐time predictions of ice conditions for operational use. This model is an adaptation of the seasonal sea ice dynamic/thermodynamic model developed at the Cold Regions Research and Engineering Laboratory (CRREL). It consists of (1) a momentum equation that includes air‐to‐ice stress, water‐to‐ice stress, internal ice stress, Coriolis force, and the pressure gradient force due to tilt of the sea surface; (2) a constitutive law that relates ice stress to strain rate and ice strength; and (3) continuity equations for ice thickness and concentration. For treating internal ice stress, the model uses a viscous‐plastic constitutive law with plastic strength dependent on thickness and concentration. A finite difference numerical procedure is used for solving the equations.

To obtain numerical simulations, the Regional Ice Model (RIM) is applied over the Beaufort Sea area using a 22 × 22 grid array with a grid distance of 42.3 km and a time step of 3 hours. Model simulations out to 48 hours are performed and the simulated drifts compared with buoy motion data collected during the period November‐December, 1979. The comparisons show the simulated drift to be in reasonable agreement with observed buoy motions.