18 November, 1999
Scientists who are interested in collaboration!
The Siple Dome deep ice core drilling project team member came to the LTER office today to talk with us and share his science. I gave a short presentation to a group of PI (principal investigator) scientists who were holding their annual spring general meeting. After explaining my project, I invited their parcticipation in the education collaboration by hosting a short discussion for the workshop parcticipants. This journal entry talking about the Siple Dome project is the direct result of Dr. Greg Lamorey coming to volunteer his expertise.
The ice core drilling project has two main goals; looking at the paleoclimate record through direct analysis of gases trapped in the ice core and looking at ice dynamics. One might ask, "what can one discover from ice cores?" First, one can get a temperature profile from the ice core called a paleothermometer. The way this works is by analysis of the gases contained in the bubbles within the ice core itself. When temperatures are cold, the trapped gas is lighter with very little carbon dioxide and oxygen. Lighter isotopes are found in the gas. When the air is warmer, there are more carbon dioxide and oxygen trapped and heavier isotopes. The record has wiggles that are the result of differences every year. As a comparison surface processes are examined in a similar way using the top layers in the snow and looking at the atmospheric interactions for the past three or four years. The gases from the three-year cores are correlated with the automatic weather station data. Looking at each layer for the three years is important also. The SOAR project (described in an earlier journal entry) parcticipates using it's radar remote sensing devices. This information is used to determine how to interpret the gases from the deep ice cores. Other gaseous compounds found in the cores such as sulfur based or other acids can be linked to volcanic events in the past.
Scientists look at fabric of the ice as part of ice dynamics. By this they mean that they are looking at the orientation of the ice crystals within the cores using a polarizing lens. Physics students will be able to explain how this works. When all the crystals are aligned in the same direction, there is no light that passes through the lens. However, when some of the crystals are at various angles, corresponding predictable patterns of color are reflected back. This will give information as to the folding of the ice.
There are two main kinds of drilling processes; hot water drilling and electromechanical drilling. The hot water drilling melts a ring around a small core of ice and grabs small chunks of ice core every 100 meters. The record is not continuous but can still yield valuable information. The electromechanical drilling is continuous and is retrieved in 1-5 meter pieces. One might ask why the pieces are taken out in such short pieces if the whole core is over 1000 meters. The reason is because of something called brittle core. A brittle core is the result of temperature, accumulation rates and depth within the core. Warmer temperatures during accumulation deeper in the ground with the most atmospheric pressure cause the ice cores to break very easily. In fact, the closing of a door has been known to cause an entire piece to explode. When brittle ice is encountered, the cores are cut into one-meter pieces before being brought to the surface by pulling a lever that activates a core dog that will cut the core. Learning from experience, the researchers have discovered that if they leave the cores in a trench about 8 meters deep through the winter and come back the next year to get them, they are not nearly as brittle and are much easier to work with. Brittle cores were encountered at about 400meters. The project is now at 1004 meters with lots of brittle cores "resting " in their trenches waiting to be brought back to the lab. Working on the cores means one must work in a cold room lab. This is not a job for the weak of heart.
There are three main kinds of scientists working on this huge project; the field scientists; the computer modelers; and the synthesizers. The computer modelers use the data collected by the field scientists to create computer models of the past and project into the future trying to understand what factors determine major climate changes. A better understanding of the past climate conditions, especially those responsible for causing the ice ages will help predictions of what the future may hold. The synthesizers look at data and computer models and develop theories. Dr. Wally Dolker from Columbia University and Dr. Richard Alley from Penn State are the main synthesizers. For example, they have attempted to explain ocean circulation patterns using some of the data from the ice core drilling projects.
Many people working here on the ice feel that major breakthroughs will be made in understanding climate and the causes of such events as the ice age. There is a future in many areas of science for bright, motivated young people who love physics, chemistry and computer modeling. According to Dr. Lamorey " much of our understanding of climate will be discovered by those young people now training for work in the field." The Siple Dome project is now 4 years old and data is just now starting to be analyzed by the synthesizers.
For more information, look on this web site: www.dri.edu/wrc/waiscores For possible parcticipation in an arctic project: www.mines.uidaho/edu/glacier/
Contact the TEA in the field at .
If you cannot connect through your browser, copy the TEA's e-mail address in the "To:" line of your favorite e-mail package.