Latitude: 82.53 degrees South
Longitude: 96.68 degrees East
Temperature: −22°C( −8°F)
Wind speed: 22 knots
Wind Chill: −37°C( −34°F)
Wind direction: not given
Elevation: 11,525 feet
Kilometers traveled: 830
Notes on daily life:
I must make an apology to everyone who has been reading these logs and following our progress. I have been reporting erroneous wind speed measurements. When I mounted the weather station anemometer to the module roof I did not leave enough clearance. As a result, strong winds have been creating turbulence close to the roof surface and reducing the true wind speed measurement. It became obvious this morning when we had a lot of blowing snow and the anemometer was only reading a wind speed of 8 knots.
To fix the problem I climbed onto the roof and moved the anemometer another four feet above the roof surface, after this the reading was 22 knots much more like it! So, I am sorry, I cannot provide accurate wind speeds for the previous days but I can assure you that from now on the readings will be far more precise. Now, on with the log…
Another 15–hour driving day, for the past few days we have been very fortunate; the surface has been good for driving, although a little bumpy at times. We have been steadily gaining altitude at a rate of 100–200 feet per day.
I have noticed that since LGT1 (the first fuel air drop site) the wind and sastrugi direction have been almost perpendicular to the surface slope (parallel to the contours) and coming from our left (approximately grid Northwest). Typically, one would expect winds in this area to be katabatic (gravity driven). Katabatic winds# occur as the high altitude air above the polar plateau becomes extremely cold and dense; the cold, dense air sinks due to gravity and forms a high–pressure center over the Antarctic Plateau. One would imagine a gravity–driven wind to flow directly down slope, however, what we are seeing here is not direct down–slope flow, we are seeing a deflection to the left. This leftward deflection is typical of high–pressure centers in the Southern Hemisphere; it is caused by the Coriolis Force.
Coriolis Force exists as a consequence of our planet's spin, it acts on all moving objects on Earth even the oceans. It is because of the Coriolis force that low–pressure atmospheric systems spin anti–clockwise∗ in the Northern Hemisphere and clockwise in the Southern Hemisphere. High–pressure atmospheric systems spin clockwise in the Northern Hemisphere and anti–clockwise in the Southern Hemisphere. That is why we are seeing the katabatic winds on the East Antarctic Plateau deflected to the left as they flow down slope.
# For a further explanation of Katabatic Winds, see the lesson in the Teacher’s resources
∗ Editor’s note: Anti–clockwise is the British equivalent of counter clockwise.
Notes on daily life:
Another long day of driving, we ran into several more deep sugary snow patches on the way to AGO4. The dozer CAT got stuck a few times, we sheared a bolt on the radar boom and the left hand towing hitch on the Aalener sled broke again. Quite an eventful day traversing really!
After dealing with all these mishaps en route, we finally reached our destination: AGO4. It was strange to approach this little scientific site after so many days in the East Antarctic wilderness with nothing but snow and ice to see. Although the AGO4 site is only composed of a small orange box building (about 16’ x 8’ x 8’), a snowmobile, some cargo boxes and a few bundles of fuel drums, it stood out on the horizon like a lighthouse on a moonless night. We were all very excited to have made it this far – about one–third of the way along the traverse.
Upon our arrival Tom and I set about collecting surface snow samples from upwind of the trains (to ensure that no contamination would occur). The rest of the crew set up our trains to camp for three days and surveyed the building and materials of the AGO4 site. After we had all taken in our new surroundings we settled down to a delicious dinner of homemade pizza (cooked without an oven), courtesy of Andrea. After dinner I sharpened the cutters for the drill so that we would be ready to collect some ice core in the morning.
The wind seems to be calming down, which is a blessing; there are few things more miserable than drilling an ice core and sampling a snow pit in a blizzard. Lets hope it stays calm.