Conceptual and Numerical Modeling of Ice in a Global Climate Framework

Abstract

Ice is both an important indicator, and agent, of climate change. In this work we consider conceptual and numerical models of ice in the global climate system on two ends of the climate modeling spectrum. On the simple end of the spectrum, we introduce a low-dimensional global climate model to investigate the role of oceanic heat transport on ice cover, particularly in the initiation of global ice cover, known as Snowball Earth events. We find that oceanic heat transport is effective at keeping the ice margin at high latitudes, and neglecting to include oceanic heat transport can lead to drastically different climate states. On the complex end of the climate modeling spectrum, we implement an iceberg parameterization in the Los Alamos National Laboratory's sea ice model CICE. Novel to our approach is we model icebergs in two frameworks - as Lagrangian particles, and as an Eulerian field. We allow icebergs to interact dynamically with the surrounding sea ice, and the modeled iceberg thermodynamics allow them to melt as they drift, serving as vehicles of freshwater injection into the ocean from land ice sheets. We focus on Antarctic icebergs, which tend to be larger than those found in the Arctic and are more likely to encounter substantial sea ice pack.