West Antarctic Ice Sheet Microstructures
Research Team Update for 2016
The VeLveT Ice Team is headed back to Antarctica this winter (2016) for their second field season. The membership of the team has shifted a bit, and they don’t have PolarTREC teacher Yamini Bala with them this year, so they are continuing a blog on SquareSpace here.
What Are They Doing?
The research team studied the microstructure of ice crystals on the West Antarctic Ice Sheet (WAIS). As the research title of their project implies, "VeLveT Ice", the team is researching what happens at the small scale of individual ice crystals that ultimately affect the large flow patterns in an ice sheet. The group is therefore studying the link between crystal properties, ice flow, and climate history because the crystal structure retains a memory of past climate which is recorded differently than "normal" ice core analyses. Ice crystals grow, rotate, and recrystallize with time and flow in an ice sheet. The rate at which each of these processes occurs depends on the temperature, state of stress, and impurity (e.g. dust, ash or salt) content of the ice. The orientation, texture, size and shape of the crystals in a given block of ice evolves through time, but also "remembers" past temperature and flow. Many scientists have observed that these microstructural properties vary with depth in an ice sheet and climate history. For example, ice from glacial time periods typically has smaller crystals, higher impurity content, and stronger fabric than ice from interglacial time periods. These microstructural properties also affect how the ice flows—ice in an ice sheet is far from a homogeneous substance and variations in properties on the small scale can affect large-scale flow patterns.
This project specifically investigated the ice microstructure, impurity content, and ice-flow patterns in relation to climate history for the ice near the West Antarctic Ice Sheet (WAIS) ice core site, using a combination of borehole logging, modeling, and thin section analyses. This work was the first to combine two novel advanced techniques for studying the relationship between ice microstructure, deformation, and climate history. More information about the project can be found here.
Where Are They?
The team flew from McMurdo, Antarctica to the West Antarctic Ice Sheet (WAIS) Divide drill site on a Hercules LC-130 airplane. The WAIS divide sits on top of 3,485 meters of ice, thicker than 9 Empire State Buildings stacked on top of one another! The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea. While on the Ice Shelf the team members slept in tents and traveled by foot, on ski, or by snowmobile to field sites within 2 km of their base camp.
Meet the Team
Yamini Bala teaches by engaging students in urban agriculture and problem-based learning in order to solve the challenges of food insecurity, obesity, and diabetes that disproportionately affect the school community. She is currently completing her MS in education at Northwestern University, and has a MA in conservation and community development from Future Generations Graduate School. As an undergraduate at Pomona College, majoring in environmental science, Yamini spent a semester abroad studying comparative ecology in Ecuador.
Her experiences there fostered a passion for traveling, learning languages, and exploring diverse cultures and ecosystems. For much of the following decade, she studied and worked in over 20 countries around the world, while maintaining a home base in Detroit, Michigan where she was engaged in non-profit youth programming and urban agriculture. In her spare time, Yamini enjoys reading, gardening, music, and meditation.
Dr. Erin Pettit is an Assistant Professor of Geophysics at the University of Alaska Fairbanks. With her interest in landscape patterns and fluid dynamics, glaciology allows Dr. Pettit to combine a background in mechanical engineering with her love of the high mountains and her interest in contributing to questions of climate change and sea level rise. Her research emphasis is in ice dynamics, ranging from the relation between ice crystal microstructure, climate history, and ice flow near ice core sites to the fast flowing calving glaciers and ice shelves as they respond to modern climate change.
In addition to working in Greenland, Alaska, British Columbia, and Washington State, she has been on eight research expeditions to remote field sites in Antarctica; for five of these she was an expedition leader. Dr. Petitt also loves teaching. As a graduate student, she developed the Girls on Ice program, an inquiry-based wilderness field experience for teenage girls that challenges them physically, intellectually, and in leadership. As a faculty member, she has developed a hands-on inquiry-based undergraduate course "Ice in the Climate System" that has students collecting lake ice cores on campus, running their own climate models, and teaching first graders about ice sheets.
Dr. Rachel Obbard is an Assistant Professor at the Thayer School of Engineering at Dartmouth College. She is a materials scientist with an educational background that spans both science and engineering and research experience in areas ranging from nanostructured thin films to the microstructure of ice. Her broad interest lies in the structure of materials, especially porous or multiphase ones, and in cross-disciplinary ways to analyze and characterize microstructure. Dr. Obbard's current research interests include ice and snow, the conservation science of cultural artifacts, and materials in sports. In her cryospheric work, she specializes in sea ice microstructure, ocean-ice-snow-air interactions, and the evolution of microstructure in ice sheets and glaciers.
Dr. Obbard holds a BS in Engineering Physics from the Colorado School of Mines, an MS in Materials Science and Engineering from the University of New Hampshire, and a PhD in Engineering from Dartmouth College. She worked as a postdoctoral fellow for the British Antarctic Survey, where she first began to study sea ice and ocean-ice-air interactions. When not studying snow and sea ice with her graduate and undergraduate students, she teaches courses in materials in sports equipment at Dartmouth and snowboarding at a local ski resort.
Tiffany graduated from the University of Alaska Fairbanks in 2014 with a BS in Geoscience-Geophysics with a minor in Mathematics. She has been assisting with various research projects in the Arctic and Antarctic for 3 years. The polar and alpine regions have been a particular interest to her during her undergraduate career. She hopes to continue on to a Master's program in polar and alpine climate change after taking some time off to travel, work, and refine her interests. This season with the Velvet Ice Expedition will be her first of what she hopes will be many more experiences in Antarctica.
In her spare time Tiffany loves to read, hike, play board games with friends, and hang out with her pets and loved ones.