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Exploring the Arctic from space

By Ruth Howells, on 20 January 2012

The first Lunch Hour Lecture of the new term was held on 17 January – the 100th anniversary of Captain Scott and his team of explorers reaching the South Pole. So the topic of scientific exploration and measurement in the polar regions is an apt one.

In a busy Darwin Lecture Theatre, an audience of all ages opened their lunchboxes and poised themselves to listen to the day’s speaker, Dr Katharine Giles from the Centre for Polar Observation and Modelling (CPOM), part of UCL Earth Sciences.

Katharine’s lecture was about understanding the physical processes taking place in the polar regions by using increasingly sophisticated satellites. Her main area of research is measuring the changes in sea ice cover in these regions.

Sea ice
Sea ice is an important part of the climate system. It doesn’t just melt and freeze, changing size and volume with the seasons, but is moved around by winds that can cause ice floes to crash together. It also forms a barrier between the atmosphere and the ocean and reflects radiation into space.

So, it’s a dynamic entity in its own right – but it’s also vital in a much wider context, as climate models predict that the polar regions are the most sensitive to climate change. Understanding changes in these regions is, therefore, important.

There have been a series of Earth remote sensing satellites used by scientists for just this purpose. Their radars can see through the atmosphere and monitor the surface of the Earth day and night.

UCL scientists have a long heritage of working with the European Space Agency (ESA) to use satellites to monitor the Arctic and Antarctic, analysing the data that they collect as the equipment has gone through various incarnations.

Duncan Wingham – now Chief Executive of the Natural Environment Research Council (NERC) – and Seymour Laxon from UCL conceived, and won funding from ESA to develop, Cryosat-1: a satellite specifically designed to measure changes in sea ice with more accuracy than ever before.

Katharine was part of a worried audience of scientists watching the launch of Cryosat-1 in October 2005 and wondering where their satellite had got to. Before things were certain, she received a text from a friend reading: “I’m sorry about your satellite.” It soon became clear that it had exploded on launch.

ESA quickly agreed to build a replacement satellite and Crysosat-2 was successfully launched in April 2010. UCL scientists have remained closely involved since the launch – analysing data and validating measurements. Although satellites have been measuring how the ice is changing for many years, scientists now have the tools to monitor how the ocean underneath the ice is changing too.

Field work
In April 2011, Katharine was part of a group of scientists who went to the Arctic to investigate how satellite radar is penetrating snow and ice cover. Her photos and videos from this trip were very evocative: from images of tame arctic wolves loitering around the camp, to a video of the team landing in a plane on the ice.

The frozen landscapes and inhospitable environment that Scott and his team of explorers faced, also presented problems for scientific fieldwork that needed carefully thought out solutions. The team’s blogs from this trip on the ESA website make for fascinating reading and have stunning images.

The data from CPOM and other scientists around the world, from satellites and ground observation, continue to point unequivocally to the fact that the ice cover and the ocean are changing.

The latest satellites mean that these changes can be monitored with unprecedented accuracy. This area of science is, therefore, not only intriguing in its own right, but critical in terms of our wider understanding of climate change.

Image: Elevation map of Antarctica from January and February 2011 from CryoSat-2 (bottom) Credit: CPOM/UCL/ESA

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