I am a PhD researcher in applied mathematics and physical oceanography with a background in engineering science and fluid dynamics. My current research focuses on improving our understanding of how the ocean impacts melting of the Antarctic Ice Sheet through a combination of theoretical investigations and numerical modelling.
the big picture
Sea level rise is one of the most impactful consequences of climate change, threatening coastal ecosystems, populations, and infrastructure all around the world. In recent decades, sea level rise has been accelerating, and a key factor that is driving this trend is increased melting of the Antarctic Ice Sheet.
The parts of the Antarctic Ice Sheet that float on the ocean while still being attached to the ice sheet are called ice shelves. These floating ice tongues can extend for many kilometers from the continent’s coastline. The largest Antarctic ice shelf covers an area of about 200,000 square miles, nearly the size of France! Since ice shelves float on the ocean, they do not cause sea level rise when they melt. However, ice shelves act as stoppers that prevent the ice grounded on land from flowing into the ocean. When ice shelves melt, it reduces their ability to stop grounded ice from sliding into the ocean. As a result, more land ice flows into the ocean, causing sea level rise.
We know from satellite data that many ice shelves around Antarctica are getting thinner. But the physical processes that cause ocean currents to drive melting are still poorly understood, which makes it difficult to predict how ice shelf melting will evolve in the future. The aim of my research is to address this uncertainty by improving the way in which ocean-driven melting is represented in climate models used for sea level rise projections.
modelling ice shelf – ocean interactions
Directly beneath the base of a melting ice shelf there is a narrow band of flow, or boundary current, which is often called the ice shelf-ocean boundary layer. Despite only being a few meters thick, this boundary current plays a crucial role when it comes to melting of ice shelves because it regulates the exchange of heat between the ocean and the ice. Large-scale climate models used for sea level projections typically employ a grid resolution that is too coarse to resolve the ice shelf-ocean boundary layer. As a result, they rely on poorly constrained parameterisations to represent the effect of small-scale boundary layer turbulence on ocean-driven ice shelf melt.
As part of my current PhD research I use high-resolution 3-D modelling techniques to study the turbulent processes that are unresolved in large-scale climate models. I use large eddy simulations (LES) and ocean model simulations (MITgcm) to investigate the physical processes taking place in the ice shelf-ocean boundary layer, and to assess their representation in commonly used parameterisations.
I have also worked extensively with a simpler 1-D plume model which allows the study of fundamental boundary current dynamics without the computational cost required to run high-resolution models. I have used 1-D plume simulations to investigate the effect of tides and subglacial discharge on ice shelf melt.
peer reviewed publications
a list of my publications can also be found on Google Scholar
- Ice shelf basal melt sensitivity to tide-induced mixing based on the theory of subglacial plumes, J. Anselin, B.C. Reed, A. Jenkins and J.A.M. Green (2023). Journal of Geophysical Research: Oceans, 128.
- Ice base slope effects in a buoyancy-forced turbulent shear flow beneath a melting ice shelf, J. Anselin, P. Holland and J. Taylor [in preparation]
below you can find a list of projects that I am currently involved in or have previously contributed to
Ice Shelf – Ocean Boundary Layer (ISOBL): NERC grant to characterise the fundamental fluid dynamics of the ocean boundary layer beneath ice shelves and to create new parameterisations for turbulence and melting (PhD researcher, PI: John Taylor)
Island Impact expedition (PS133-2): research cruise aimed at investigating sources and transport pathways of iron around South Georgia and downstream of the archipelago along the flow of the Antarctic Circumpolar Current (Physical Oceanography team member, PI: Sabine Kasten)
Southern Ocean – Carbon and Heat Impact on Climate (SO-CHIC): multi-institute project to understand and quantify variability of heat and carbon budgets in the Southern Ocean (Tier 2 glider pilot, BAS contact: Alex Brearley)