The Antarctic Peninsula – a mountainous region extending northwards towards South America – is warming much faster than the rest of Antarctica. Temperatures have risen by up to 3 oC since the 1950s – three times more than the global average. This is a result of a strengthening of local westerly winds, causing warmer air from the sea to be pushed up and over the peninsula. In contrast to much of the rest of Antarctica, summer temperatures are high enough for snow to melt.
This summer melting may have important effects. Meltwater may enlarge cracks in floating ice shelves which can contribute to their retreat or collapse. As a result, the speed at which glaciers flow towards the sea will be increased. Also, melting and refreezing causes snow layers to become thinner and more dense, affecting the height of the snow surface above sea level. Scientists need to know this so they can interpret satellite data correctly.
Dr Nick Barrand, who carried out the research while working for the British Antarctic Survey, led an analysis of data from 30 weather stations on the peninsula. "We found a significant increase in the length of the melting season at most of the stations with the longest temperature records" he says. "At one station the average length of the melt season almost doubled between 1948 and 2011."
...Dr Barrand, who now works at the University of Birmingham, says, "We found that the model was very good at reproducing the pattern and timing of the melt, and changes in melting between years. This increases confidence in the use of climate models to predict future changes to snow and ice cover in the Antarctic Peninsula."...
Mountains on the Antarctic Peninsula, shot by NASA / Maria-Jose Vinas, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license
No comments:
Post a Comment