We present a new brittle rheology and an accompanying numerical
framework for large-scale sea-ice modelling. This rheology is based on a
Bingham-Maxwell constitutive model and the Maxwell-Elasto-Brittle (MEB)
rheology, the latter of which has previously been used to model sea ice.
The key strength of the MEB rheology is its ability to represent the
scaling properties of simulated sea-ice deformation in space and time.
The new rheology we propose here, which we refer to as the brittle
Bingham-Maxwell rheology (BBM), represents a further evolution of the
MEB rheology. It is developed to address two main shortcomings of the
MEB rheology and numerical implementation we were unable to address
previously: excessive thickening of the ice in model runs longer than
about one winter and a relatively high computational cost. In the BBM
rheology and numerical framework these shortcomings are addressed by
demanding that the ice deforms under convergence in a purely elastic
manner when internal stresses lie below a given compressive threshold.
Numerical performance is improved by introducing an explicit scheme to
solve the ice momentum equation. In this paper we introduce the new
rheology and numerical framework. Using an implementation of BBM in
version two of the neXtSIM sea-ice model (neXtSIMv2), we show that it
gives reasonable long term evolution of the Arctic sea-ice cover and
very good deformation fields and statistics compared to satellite