16 December, 2002

Wilco Wilco

Date: 12/16/02

Latitude: 83 degrees 30' 02.81" S

Longitude: 104 degrees 59' 12.73" W

Time of Observations: 11:00 PM local time

Temperature: -22 C / -8 F

Wind speed: 12 knots

Wind Chill: -34 C / -29 F

Wind direction: Northeast

Meters of ice collected: 273 m

by Gordon Hamilton

The inhabitants of the Blue Room woke this morning to a slightly less annoying noise from the wind generator during strong winds the blades scream like a banshee and reverberate the noise through the Blue Room as if it were a loud speaker. Today, the quieter sound meant that the wind had slowed. Not that it had stopped altogether. Still, there was no blowing snow, there was blue sky above and the sun was shining again. Another great day in West AntarcticaŠ

The first task of the day was to dig out from yesterday's storm. The amount of snow that can accumulate around obstacles never ceases to amaze. There were drifts over a meter high along the sides of the traverse vehicles. Lynn, Carl, Brian and Jim spent the early part of the morning moving snow with shovels. Mark, Susan, Paul and Dan had some shoveling of their own to do out at the drill site. Once the drill site was open for business, Markus collected several shallow cores that he and Betsy processed later in the day at their atmospheric sampling tent. The main drilling group made good progress and finished the day at a depth of 51 meters.

Blue and Gordon made the 2 km trek out to their mass balance marker site that they started installing on Saturday. Not surprisingly nearly everything was buried in a snow drift. After a few hours work, the site was complete. The purpose of the markers is to measure the rate of ice sheet thickness change (or its mass balance). One of the most important problems in modern glaciology is understanding whether the ice sheets in Greenland and Antarctica are getting bigger or smaller with time. If they get smaller, sea level will rise. As you might imagine, the vast size and remote location of the polar ice sheets poses special problems when trying to measure their behavior. Blue and Gordon use very precise GPS (Global Positioning System) surveys to measure the vertical velocity at different sites along the ITASE traverse. They compare the vertical velocity (the speed that a hypothetical snowflake flows downwards and outwards on its way to the ocean) with the snow accumulation rate. For an ice sheet to stay the same thickness with time, the downward vertical velocity needs to be balanced by the speed that new snow is added. Snowfall exceeds vertical velocity if the ice sheet is thickening. The snow accumulation rate is obtained from studying ice cores. There are lots of different techniques for dating an ice core Gordon and Blue use layers of radioactive snow from nuclear bomb tests carried out in 1955 and 1965 to tell how much snow has fallen since then (the long-term average accumulation rate). At each site they drill two cores. Today, the first 20 meter core was drilled. Blue and Gordon drilled the first 12 meters before dinner. After a warming Mexican meal, Andrea and Lynn drilled the remaining 8 meters while Gordon processed the samples. They got finished a few minutes after 10:00 PM, just as Lynn thought he was going to start earning overtime pay!

It is fine evening at Site 2. Tomorrow we will finish the remaining science projects, pack the sleds and hit the road for Site 3. With all the new sastrugi that formed during the storm it might be a bumpy rideŠ