Podcast episode 4 - Published 20 July, 2017 by Nicholas O'FlahertyTweet
This week, in our podcast, we speak to Professor Helen Amanda Fricker of the Scripps Institution of Oceanography, at the University of California San Diego.
In 2007 Helen led a team that detected an active subglacial water system under the Whillans Ice Stream by using data from NASA’s ICESat satellite. The hydrological system consisted of several interconnected subglacial lakes, one of which was named Lake Whillans.
The ice sheets of Antarctica and Greenland drain into the sea via ice streams – zones of ice that move faster than surrounding ice on the ice sheet. Some ice streams in Antarctica flow as fast as 2km per year. Water often lubricates the flow of the ice streams over the bedrock below, as the high pressure at that depth lowers the freezing point.
In the summer of 1969-1970, radio-echo sounding flights over the West Antarctic Ice Sheet identified for the first time a number of ice streams entering the Ross Ice Shelf. One of those ice streams was subsequently named the Whillans Ice Stream in honor of US glaciologist Ian Whillans.
Helen Amanda Fricker became one of the primary investigators in the Whillans Ice Stream Subglacial Access Research Drilling project (or WISSARD). The team spent many years devising a safe sampling procedure for sub-glacial lakes. Contamination in the drilling process could cast doubt on any life found, as well as run the risk of introducing invasive organisms into the lake.
Finally in January 2013, the WISSARD team successfully drilled down into Lake Whillans and obtained the first sample ever retrieved directly from a subglacial lake in Antarctica.
For more information on the WISSARD project:
In this podcast, Professor Helen Amanda Fricker also talks about the ROSETTA Project, which will commence its third field season in Antarctica later this year, with aerial and ocean-based surveys of the Ross Ice Shelf.
The ROSETTA research program aims to conduct a detailed survey of the Ross Ice Shelf, primarily through flying back and forth over the ice shelf in a LC-130 aircraft to create a grid of the information collected. The LC-130 is equipped with an “IcePod”, which contains various scientific instruments to collect aerial measurements and create a detailed map of both the ice shelf and the sea bed below it.
The IcePod collects a range of information, including ice surface elevation (using LiDAR), ice thickness (using radar), and the shape and materials of the ocean floor beneath the ice shelf (using gravity and magnetic measurements).
As well as aerial surveying, the ROSETTA researchers also use six “Alamo drifters”, floating units deployed into the ocean in order to collect data on ocean circulation along the front of the ice shelf. Matching this circulation data with the grid map created by aerial surveying will help to improve scientific models of how increasing sea temperatures can lead to additional melting of the ice shelf.
For more information go to the ROSETTA Project
Feature image: Drilling into sub-glacial Lake Whillans, credit: Reed Scherer, WISSARD Project