Warmer air over the snows

The Antarctic Peninsula has seen warmer air temperatures than most of the rest of Antarctica, causing the widespread retreat and even collapse of many ice shelves in the area. This is problematic because it causes rapid acceleration of the glaciers which fed these ice shelves and were simultaneously buttressed by them, resulting in further ice mass loss.

Warmer air temperatures can cause a change in the firn (old, compacted snow that has not yet turned to ice) layer and facilitate the opening and growing of crevasses, both of which can influence the stability of ice shelves.  The surface energy balance, detailing the energy transfer between the atmosphere and snow, has been studied surprisingly little considering the devastating effect it has had on many Antarctic ice shelves. Kuipers-Munneke and his colleagues use weather stations on the Larsen-C ice shelf to build and test a model of how energy from the atmosphere is transferred into the ice to cause melt and changing snow and ice properties.

They find that in many summers, surface melt occurs during long calm periods even when temperatures are negative just 2m above the ground. This highlights the need for high-quality energy balance models – clearly air temperature is far from a perfect indicator of surface melt. The team find a north-south gradient in many energy-balance components and the resulting temperature, which also causes a melt gradient.

Given the recent decreasing melt trends discovered at the Antarctic Peninsula, which are thought to be due to long-term (interdecadal) climatic fluctuations, it is crucial to understand and model how the energy balance and melt in this fast-changing area develop and what factors drive it.

Ice2sea Work Package: WP3.2

Publication: Kuipers Munneke, P., G. Picard, M. R. van de Broeke, J. T. M. Lenaerts, and E. van Meijgaard (2011), Insignificant change in Antarctic snowmelt volume since 1979 , Geophysical Research Letters.

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