Friday, December 28, 2007

December 29, 2007
WAIS Divide camp Antarctica

Time: 6 am
Latitude: 79° 28.10’ S
Longitude: 112° 3.56’ W
Elevation: 1820 m (5919’)
Temperature: -14 °C ( 7°F)
Wind speed: 14 km/h (8 mp/h)
Wind Chill: -7°C ( 25°F)
Visibility: 1600 m
Clouds: cirrus, mist
Wind direction: W
Relative Humidity: 76%
Barometric Pressure: steady
Precipitation: 0
Breakfast: eggs, bacon, sausage, toast
Lunch: fish and chips, chicken soup, vegi soup

The biggest news was that yesterday was crystal clear. Ken and I had been waiting for a sunny day to film our snow pit. Since I had scraped the dividing wall between the two pits to only 15 cm thick (6”) it was primed and ready for viewing snow/ice layers. We ran out there before 6 am and it was perfect timing as the Sun was shining into the open pit. One of the pits is completely open on top and the one you stand in to view the adjoining wall is completely covered with plywood sheets. Once your pit is darkened you can see the light illuminate the wall, and it was a spectacular view of beautiful wind blown and storm layers. Last summer’s hoar frost layer was easily identified so the accumulation of snow for the last two years can be determined. The snow accumulation rate here is ~85 cm per year (25 cm of ice), so in our ~2 m deep snow pit you can see almost all of two year’s worth of snow.

Students are still on vacation so not too much on my 3d quadrat but suffice to say that the bamboo structure is doing well and surviving the conditions. In a place like West Antarctica where you can often see to the real horizon not obstructed by buildings, trees, or hills (about 11km 0r 7 miles) it is very easy to look at the mega (large) scale of this place. My 3d quadrat allows me to focus on the meso (medium) and micro (small) scale of West Antarctica. IT is a little cold and breezy just to sit outside and observe the snow surface but I can tell you that for the 10 minutes I observed the surface is very dynamic. If you have ever stood on a beach (especially a very white one) and just observed the grains move in the wind it looks similar to the snow surface here (minus the swim suit). The snow “flakes” that fall here are not very soft and fluffy but largely coarse and crystalline. Once those coarse “flakes” hit the ground, and because it is so dry, the flakes do not stick but act almost as little individual crystalline pieces that roll around on the surface. Around all objects that stick into the surface you can incredible erosion and deposition of snow. On the up wind side there is the most erosion where snow flakes are picked up and moved to the back side of the object and deposited. A similar pattern emerges around tents, bamboo poles, buildings, cargo piles, snowmobiles, the outhouses, etc. Erosion up wind and deposition down wind. It creates a spectacularly beautiful consistency to the landscape. That erosion and deposition pattern becomes very apparent here during and after storms where a snow bank 2 m (6’) high might form over night. Even during normal conditions I have to shovel out part of my tent every week or so to keep it clear of snow, or as it is called here – spin drift.

If there are no objects, then the snow surface it generally very very flat. To us cross-country skiers it is a paradise where you can move across a relatively flat surface for kilometer after kilometer. Where I live in Maine, I never get to ski a flat surface for more than a few tens of meters. What I have to ski on at home is up, or it is down, and very little in between. Take time to observe the very small in your 3d quadrat and you will be amazed as to the patterns and things you observe and how it connects to the entire landscape.

Happy Birthday today to Ursula, one of the core handlers. Last night we had cake and sang Happy Birthday.

Today’s images are of inside the snow pit. The very light layer just above Inger’s finger is last year’s summer snow-hoar frost layer(s). The second image is of the Twin Otter that spent the last two days here flying missions with the geophysics guys. The third image is a view taken from the Twin Otter of WAIS Divide camp. The image is annotated to point out some highlight.

1 comment:

Brandon Gillette said...

So happy to hear that the Penn State crew finally got an otter out there! Happy New Year!