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| 2001 Team |
Steve Arcone
Science Investigator
Cold Regions
Research and Engineering Lab
Hanover, New Hampshire
My name is Steven Arcone and I work at the U. S. Army Cold Regions Research and Engineering Laboratory (USA CRREL) in Hanover, New Hampshire. I came to this area in 1973 to get a PhD at nearby Dartmouth College and have worked here since then. My research involves using subsurface radar for gaining information on the structure of snow, ice, permafrost, and just about any kind of dirt that a glacier left behind. If you live in the northern United States or even along the Mississippi Valley, chances are you are standing on dirt that I like! My radar sends out very short pulses so I can see layers in dirt and ice, and I try to relate those images to the real situation. I used to be a radar engineer at an aerospace company and that's how I know about radar. In the past twenty years my research has taken me to many glaciers in Antarctica and Alaska. Radar and glaciers are a good mix because radiowaves travel very well in ice.
Along the ITASE route in West Antarctica I use my radar to profile the snow layering for the last 200 years and more. I drag the radar antennas on the ground to get very precise data. Recording from a helicopter is fun, but we are too far from base to do that, and the vibration of the helicopter makes a noisy radar profile. So far our radar has shown that the layers at our core sites are nearly horizontal and so we have chosen good sites because the firn will probably not have been disturbed for this period of time. In some places however, layers are dipping appear folded, and sometimes seem to fade. These dipping layers could be caused by unequal rates of snow fall around hills, or by ice deforming as it travels over a buried mountain, which might even be a volcano! In 2001 we found places where the layer reflections were very strong. These could be areas where strong storms may have dumped a lot of chemicals or dust. If you read about the other researchers on this expedition they will tell you what these chemicals could mean.
Finding layers in Antarctica is easy because they are everywhere. In any one spot the layers could be formed by dust, melting, refreezing, and recrystallization, but we are now pretty sure that the ones I am recording are caused by ions of mainly potassium, calcium and sodium. When I record my radar records I do so by sending out a lot of signals over and over, and then adding up the echo traces 32 at a time so that I am actually recording very slowly. In this way all the reflections from the more random dust and density changes cancel each other out, and leave just the reflections from the evenly distributed chemical ions. These reflection layers extend for miles and miles without changing their amplitudes, so it appears that these chemicals are well mixed in the atmosphere before they are deposited with or without snow, and that our cores well represent the regions from they were obtained.
