Molecular-dynamics simulation of clustering processes in sea-ice floes

TL;DR

This paper models sea-ice floe dynamics using a granular gas analogy, employing simulations to analyze clustering behavior influenced by ice concentration and floe size distribution.

Contribution

It introduces a novel particle-level model for sea-ice floe interactions based on granular gas principles, including a new numerical simulation algorithm.

Findings

Clustering behavior varies with ice concentration.

Two distinct clustering regimes identified.

Cluster size distribution follows different power-law exponents.

Abstract

In seasonally ice-covered seas and along the margins of perennial ice pack, i.e. in regions with medium ice concentrations, the ice cover typically consists of separate floes interacting with each other by inelastic collisions. In this paper, hitherto unexplored analogies between this type of ice cover and two-dimensional granular gases are used to formulate a model of ice dynamics at the floe level. The model consists of: (i) momentum equations for floe motion between collisions, formulated in the form of a Stokes-flow problem, with floe-size dependent time constant and equilibrium velocity, and (ii) hard-disk collision model. The numerical algorithm developed is suitable for simulating particle-laden flow of $N$ disk-shaped floes with arbitrary size distribution. The model is applied to study clustering phenomena in sea ice with power-law floe-size distribution. In particular, the influence of the average ice concentration $\bar{A}$ on the formation and characteristics of clusters is analyzed in detail. The results show the existence of two regimes, at low and high ice concentration, differing in terms of the exponents of the cluster-size distribution and of the size of the largest cluster.