Simulations of the consolidation process in first-year sea ice ridges

Abstract

A two-dimensional finite element model has been used to simulate the temperature development in first-year ice ridges and in the surrounding level ice. The program ABAQUS has been applied with user-defined subroutines to calculate the thermal loads. Meteorological weather data is used as input into these sub-routines and the sensible (convective) flux, the latent flux and the long- and short-wave radiation from the surface is calculated. Two material models have been applied: (1) a composite material consisting of sea ice and water with ordinary sea ice/water thermal properties, and (2) a homogeneous equivalent material. The measured growth of the consolidated layer in three first-year sea ice ridges has been simulated. However, modifications of the conductive model have to be done in order to handle the initial phase in which convection is crucial. One-dimensional simulations have been used to estimate the theoretical limit of the ratio of the thickness of the consolidated layer to the thickness of the level ice. Limit values as functions of the porosity have been found. The question whether this limit is a maximum value or not, is determined by processes in the initial phase. If the consolidated layer during the initial phase does not exceed this limit value it becomes a maximum, and vice versa.