‘Mowing the lawn’ at high altitude

This is the third installment of a series of reports on the 2009/2010 research season in Antarctica by polar scientist Nick Frearson. This ICE Bridge mission has been named “mowing the lawn”.

The ICE Bridge mission has been so successful that eight flights will be added keeping us in Chile until Thanksgiving. Using a DC-8 as a data collection platform has allowed us to collect an incredible amount of data in just over two dozen flights. One highly-efficient flight pattern has been dubbed “mowing the lawn” as the plane flies at low altitude in carefully spaced lines over an area.

While these flights can collect excellent tightly spaced data lines, much like mowing your own lawn, flying the same area over and over can be repetitive without new things to see or discuss. In a recent flight over Crane Glacier we took 16 passes over the ice, covering about 7000 sq. km. This is the largest area ever mapped with the laser (LVIS), and it was all accomplished in one DC-8 flight.

Our team is very happy with the low level gravity data collected over Pine Island Glacier, or “PIG” as it is affectionately called. We have also captured data in the channel under the ‘snout,’ where the glacier extends off the land and over the bay. Water in the channel warms and melts the ice above it. We hope to find out how much water these channels hold, to calculate the changing melt rate at the edges of the ice sheet. With our extended stay we hope to collect data on several additional glaciers, including the Larsen C ice shelf which we flew over for a second time yesterday to produce better gravity maps.

Nick Frearson is a senior engineer at Columbia University’s Lamont-Doherty Earth Observatory specializing in providing and maintaining airborne geophysics installations for use in both the Arctic and Antarctica. Nick has spent several seasons in the field in both the north and south polar regions, most recently as part of the International Polar Year AGAP team that mapped the large mountain range hidden under the East Antarctic Ice Sheet. Nick will be working as part of the ICE Bridge project..

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