ESA's ice mission
ESA’s Earth Explorer CryoSat mission, launched on 8 April 2010, is dedicated to precise monitoring of the changes in the thickness of marine ice floating in the polar oceans and variations in the thickness of the vast ice sheets that overlie Greenland and Antarctica.
With the effects of a changing climate fast becoming apparent, particularly in the polar regions, it is increasingly important to understand exactly how Earth’s ice fields are responding. Diminishing ice cover is frequently cited as an early casualty of global warming and since ice, in turn, plays an important role regulating climate and sea level, the consequences of change are far reaching.
For some years now, satellites such as ESA’s Envisat have been mapping the extent of ice cover. As stated in the Climate Change 2007 Synthesis Report by the Intergovernmental Panel on Climate Change, “Satellite data since 1978 show that annual average Arctic sea-ice extent has shrunk by 2.7% per decade.” However, this is only part of the picture.
In order to understand fully how climate change is affecting these remote but sensitive regions, there remains an urgent need to determine exactly how the thickness of the ice, both on land and floating in the sea, is changing. By addressing this challenge, the data delivered by the CryoSat mission will complete the picture and lead to a better understanding of the role ice plays in the Earth system.
The CryoSat-2 satellite replaces the original CryoSat, which was lost owing to a launch failure in October 2005. Following the loss, the mission was judged to be even more important than when it was first selected for development, and the decision to rebuild was taken. Almost exactly four years to the day after that decision, the new CryoSat-2, with a number of improvements, was ready for launch.
From an altitude of just over 700 km and reaching latitudes of 88°, the CryoSat-2 satellite will monitor precise changes in the thickness of the polar ice sheets and floating sea ice. CryoSat’s original objective was to determine if there was a trend towards diminishing ice cover. There now seems little doubt that there are indeed trends – the challenge now is to characterise them.