BLACK and BLOOM
This NERC-funded project aims to unravel the variations in the albedo of the Greenland Ice Sheet as a result of interactions between microbes and particulates. The darker the ice sheet surface is the more it melts, so microbes and particulates could increase the rate at which sea level rise occurs.
I am using two main approaches to examine whether microbes and particulates could be important controls on melting:
- Satellite observations to characterize the reflectivity (albedo) of the ice sheet surface. In particular I am looking for signs of algal growth and black carbon and to see whether there are any local and regional patterns in their location.
- Regional climate modelling to project the potential impact of algal growth and black carbon upon melting of the ice sheet in the future, by including their impact upon albedo in the model scheme.
The project brings together a range of experts in micro-biology, atmospheric chemistry, ice sheet mass balance and remote sensing. There are several large field campaigns planned (of which I am a part) in order to make measurements of algae, black carbon and melting on the ice sheet surface. During summer 2016 we focussed on understanding the evolution of dark ice in the south-western Greenland Ice Sheet.
The whole project consists of four work packages delivered across five institutions along with several other partners. See the project website for more details.
Greenland Ice Sheet dynamics
Each summer, areas of the Greenland Ice Sheet’s surface melt. Observations show that this surface meltwater can drain to the bed of the ice sheet via supraglacial lake drainage, moulins and crevasses.
Once this meltwater arrives at the ice sheet bed it changes the amount of friction and contact between the ice and its bed. In turn this allows surface meltwater to affect the speed at which the ice flows downhill.
I examined the impact of this effect over sub-daily and up to decadal timescales. I showed that land-terminating margins in the south-west of the ice sheet have been slowing down over the last 15-20 years in response to increased surface melting.
My findings suggest that at land-terminating margins, increased surface melting caused by projected climate change will not result in ice flow speed-up.
Please see my published papers for more.
Greenland Ice Sheet hydrology
The hydrology of the Greenland Ice Sheet is important not only in modifying ice flow (see above) but also for determining the rate at which meltwater drains into the ocean, and for evacuating sediments and nutrients from beneath the ice sheet.
I am involved in monitoring the amount of water that drains out the front of Leverett Glacier. I work with colleagues in biogeochemistry to estimate fluxes of iron, phosphorus and other nutrients from the ice sheet.