Much of my research focuses on ocean-terminating or “tidewater” glaciers. These glaciers are some of the fastest-changing kinds of glacial environments.
My PhD thesis, Frontal processes on tidewater glaciers, looked at plumes which form when fresh subglacial water is released from beneath the front of a tidewater glacier. This water rises along the ice front, entraining warm salty water from its environment, and this leads to melting of the ice front. I took a mathematical model of the plumes which form beneath ice shelves, and adapted it to the tidewater case, taking into account the vastly different geometry of the plume.
As well as the direct loss of ice due to this melting, there is also an indirect loss, as the removal of submarine ice can destabilize the ice front, leading to iceberg calving. In a paper from my PhD work, I showed that the changes in the stress due to this undercutting may lead to iceberg calving at a rate several times greater than the initiating melt rate.
Along with colleagues at Swansea University, I have been investigating particular modes of iceberg calving. In particular, we have focused on large events such as this one at Helheim Glacier in south-east Greenland. These events seem to occur when ice flow drives part of the glacier below flotation, leading to large crevasses forming at the base of the glacier. We documented this process using timelapse photography and stereo photogrammetry in a recent paper in Nature Geoscience.
Recently, I have been looking at how varying parameterizations of iceberg calving can cause different patterns of stable ice front positions in simple models. This should lead to improved ways of distinguishing between calving processes using sparse observations. I presented some early results from this at the AGU Fall Meeting in 2014.
The routing of meltwater beneath a glacier is one of the classical hard problems in glaciology. Although this has been heavily studied beneath mountain glaciers, and more recently ice sheets, there is still a lot of work to be done in the tidewater context. I have been working together with the CRIOS project to couple a simple hydrology model to Faezeh Nick’s tidewater glacier model, for application to glaciers in Svalbard.