Gas transport in mushy layers, with applications to sea ice

Significant ice-atmosphere gas fluxes have been measured for different species, but both their magnitude and seasonal variability is poorly understood. Observations of surface fluxes exist for carbon dioxide and methane (Nomura et al., 2010; Van der Linden et al., 2020; He et al., 2013; Kort et al., 2012). Modelling of these gases is required to provide sub grid scale parameterisations of their observed ice-atmosphere fluxes for future Earth system & climate models.
Halogen compounds have also been observed in sea ice. The release of these gases, such as bromine, from the ice has been linked to sudden localised depletion in tropospheric ozone (Jones et al., 2006).
Finally, both Arctic and Antarctic sea ice is a habitat for photosynthetic algae and other microorganisms (Arrigo, 2017; Caron et al., 2017). Therefore the modelling of biologically active gases, such as carbon dioxide, is intimately linked with
the study of sea ice biogeochemistry (Vancoppenolle et al., 2013; Vancoppenolle and Tedesco, 2017).

Sea ice also undergoes a seasonal cycle of cooling and warming during which the relative fractions of solid ice, liquid and gases change (Petrich and Eicken, 2017). At typical conditions most impurities cannot be accommodated in the solid ice
lattice, and so are rejected into the liquid brine inclusions. This leads to chemical concentrations in sea ice brines that are substantially elevated from the underlying ocean. Hence the physics of phase change and transport in the porous sea ice serves to moderate a biogeochemical reactor in the ice. A key barrier to investigating these processes in sea ice is understanding the complex multiphase physics of transport in a reactive porous medium.

Research Aims
My research aims are divided into two categories, primary (P) and secondary (S). The primary aims will be addressed first and will form the basis of my first thesis chapter/publication. The secondary aims consist of several different directions that could be explored. The second and third chapters of my thesis will consist of a selection of these. See fig. 1 for a proposed timeline for the project.