Details of Award
NERC Reference : NE/G013780/1
Dynamics and stability of marine ice sheets
Fellowship Award
- Fellow:
- Dr R Sayag, University of Cambridge, Applied Maths and Theoretical Physics
- Grant held at:
- University of Cambridge, Applied Maths and Theoretical Physics
- Science Area:
- Terrestrial
- Marine
- Freshwater
- Earth
- Atmospheric
- Overall Classification:
- Earth
- ENRIs:
- Global Change
- Environmental Risks and Hazards
- Science Topics:
- Glacial & Cryospheric Systems
- Geohazards
- Climate & Climate Change
- Abstract:
- Ice sheets are a major component of the Earth climate system. Ice covered surfaces can strongly bias the amount of solar energy absorbed by earth, and ice sheets are buffers of fresh water that once melted may affect the ocean circulation. Present ice sheets store fresh water of an amount that is equivalent to about 70 meters of sea level rise. Hence, understanding the dynamics of ice sheets is important in the context of the climate system as well as natural hazards. Ice sheets spread under their own weight, they gain mass from snowfall and lose mass through melting or ice-berg calving. Marine ice sheets, such as West Antarctica, rest on a bed that is about a kilometer below sea level, hence their dynamics are also affected by the surrounding ocean. Observational evidence suggest that massive parts of ice from marine based parts of the Antarctic and the Laurentide ice sheets may have been discharged relatively abruptly during the last ice age. The nature of the flow of marine ice sheets varies significantly because of the different conditions at the ice base where it is grounded compared to where it is floating over an ocean. A key component to the dynamics of marine ice sheets is the location at which the ice is thin enough to float, known as the grounding line. Early idealized studies suggested that conditions at the grounding line may be critical to the stability of a steady marine ice sheet (Weertman hypothesis, 1974). Specifically, the bed slope at the vicinity of a grounding line can be such that under small changes (e.g., in snow accumulation or sea level), a significant portion of the ice sheet can collapse. Given the configuration of west Antarctica, this implied that the hypothesis, suggested by Huges in 1973, that West Antarctic ice sheet may be disintegrating at present, may indeed be valid. One of the difficulties in understanding the dynamics of marine ice sheets arises because the conditions at the grounding line are not well understood. In addition, the complexity of the problem is such that present numerical simulations of marine ice sheets are unreliable. Introducing laboratory experiments to the research of marine ice-sheets opens a wide spectrum of opportunities to advance the understanding of the fundamental physics involved and to assess the numerical tools. The outline of my research goals in this fellowship is therefore to combine theoretical tools and laboratory-scale fluid mechanical experiments to study the stability and dynamics of marine ice sheets. Specifically I will (1) design and set up an experimental apparatus that will simulate a marine ice sheet and an ocean using a non-Newtonian fluid representing ice and a denser fluid that represents the ocean water; (2) Develop theoretical solutions of non-Newtonian sheet-shelf flow across a grounding line, and compare them against the experiments; (3) Use the comparison insights to extract the important physics at the grounding line and refine the mathematical models; and (4) Use theoretical tools and the experimental apparatus to study the stability of the grounding line position to (i) perturbations in quantities such as snow precipitation rate, sea level; (ii) bed lubrication and different profiles of bed topography; and (iii) shelf buttressing effects. The results of such research may give scientists in the glaciological community solid evidence of behavior that is so far controversial. Advancing our understanding of marine ice sheet stability, and consequently improving our ability to assess the condition of the West Antarctic ice sheet, can help the public and policy makers long range planning.
- NERC Reference:
- NE/G013780/1
- Grant Stage:
- Completed
- Scheme:
- Postdoctoral Fellow (FEC)
- Grant Status:
- Closed
- Programme:
- Postdoctoral Fellowship
This fellowship award has a total value of £235,020
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DI - Staff | DA - Estate Costs | DA - Other Directly Allocated | DI - T&S |
|---|---|---|---|---|---|
| £3,950 | £79,656 | £89,120 | £30,716 | £24,317 | £7,259 |
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