Greenland Lakes 2006
This was the first year of a 3-year UW/WHOI project jointly funded by NSF and NASA to investigate the rapid drainage of the large lakes that form each summer along much of the Greenland Ice Sheet’s western flank.
When water from these lakes fills a crack, the water, which is denser than ice, can "wedge" the crack open so that it fractures all the way to the base of the ice sheet. This process allows surface melt water to penetrate through the kilometer (0.62-mile) thick ice and lubricate the base to speed up the ice-sheet flow. During this first year Ian Joughin (UW), Ian Howat (now at Ohio State), and Twila Moon (UW) traveled to Greenland to place a suite of sensors in and around two supra-glacial melt lakes located roughly 100 km (62 miles) from Ilulisat, Greenland. They installed GPS receivers, seismometers, and weather stations along the shoreline of these lakes, which they simply named "North Lake" and "South Lake". They also placed pressure sensors in the lakes to measure lake level every 20 minutes and performed sonar surveys of the lake from a rubber raft.
Iceberg, Jakobshavn Isford, Greenland
This large iceberg calved from Jakobshavn Isbrae, the largest outlet glacier on Greenland's west coast. The horizontal dimensions likely exceed 1 km (0.62 miles) and it is roughly 500-m (0.31 miles) thick. The relatively square horizontal shape and the fact that it has capsized, suggests it calved from the floating extension of the winter ice front. During summer, when the glacier calves from a grounded ice front, icebergs tend to topple onto their sides.
|
|
|
