Pre-JIRP Readings and Discussion Questions

JIRP has rolled out some pre-expedition readings to students participating in the 2015 field season. We have heard from students in past years that they wanted more content before the season begins so we have answered that call and will be posting both discussion/reflective questions and details on student projects here on this blog. Over the next 11 weeks, students will be able to check here for the weekly post which will either pose questions on your readings or give you a detailed outline on one of six student projects on deck for this summer.

We encourage students to begin the process of engagement by participating in the discussion in the comment section. You will have a chance to ask questions of the Principal Investigators on the student projects and start learning from one another.

The questions this week are posed by two of our faculty and relate to your reading of Post and LaChappelle, Glacier Ice.  Students were asked to READ THE TEXT of this coffee table book.  

Our first set of questions are from Dr. Shad O'Neel. "Image 38 in Glacier Ice shows the 'three congruent glaciers'. We often talk about how climate is a principal control on glacier mass balance (glacier health) - aren't they supposed to be the 'canary in the coalmine'? How can the behavior in this image be explained? What is a less obvious control on the health of these glaciers? What are some other controls that may not apply to all glaciers but certainly produce examples that buck the mainstream trends?"

Our second set of questions are from Dr. Jeffrey Kavanaugh. "A defining characteristic of glaciers is that they move, slowly making their way down slope under their own immense weight. This motion is evident throughout the photographs presented in Glacier Ice and includes both viscous behaviors (where ice flows like a thick fluid) and brittle behaviors (where ice fractures like a rigid solid). What features visible in the photographs demonstrate these two forms of motion? Under what conditions or in what areas does flow appear to be fluid-like? Where do brittle behaviors seem to dominate?"

Photo by Ben Partan

A Reconnaissance Mission with GPS Receivers

By Brooke Stamper

With safety training and ski practice behind us at Camp-17, we have begun to “hit it hard” as M. M. Miller would put it. Our daily routines have transitioned from gearing up to be outside and gathering our “glacier legs”, to spending time inside working on our research  projects.  The opportunities for place-based education are endless on the icefield and many students are taking advantage of the resources provided. I recently took advantage of an opportunity to set up GPS satellite receivers with Jason Amundson, Assistant Professor of Geophysics at the University of Alaska Southeast.

Jason and I rode on a snow machine and towed “the coffin”, a storage container with the bulky equipment in it. We traveled seven miles down glacier to a predetermined transect and placed our first of four satellite receivers just below the equilibrium line altitude, where the annual average snow accumulation and ablation are equal. We placed an additional three receivers at equal distances upglacier until we were at the convergence of the Matthes Glacier and Taku Glacier.  The GPS receivers will continuously track the velocity of the glacier over a one-week period to determine what portions of the glacier respond most strongly to meltwater input, and to what degree.  The project is simply exploratory at this stage.  Our hypothesis is that the daily variation in glacier velocity will be higher in the ablation area rather than on the “high ice” in the accumulation area.

The historical and current GPS data collection has been at specific points on the icefield to gather long-term annual data on surface elevation and velocity.  Most notably, Scott McGee and Ben Slavin set up stakes at set locations along a line that runs across the Taku Glacier from JIRP’s Cook Shack to Shoehorn Peak as well as a second set of stakes directly parallel to those stakes but starting from our favorite outhouse, curiously named “Dream Land”. On these stakes are placed black trash bags to allow us to better see the daily flow of Taku Glacier.  Eventually, the stakes will begin to arc and there will be noticeable change in location of the stakes. This will give us a fantastic example of strain on the icefield and an explanation as to why there are more crevasses on the edges of glaciers as compared to the center. Because the margins of the glacier are influenced by friction, the differences in flow rates are greater; therefore, there are more crevasses we must mind when downhill skiing from the Nunatak that Camp-10 sits on.

Although all of the students have begun to work independently on our projects, we are all aware that our efforts, in total, are for the betterment of the knowledge and understanding of the Juneau Icefield. Together as classmates and expedition-mates we are all here for the furthering of science on glacial dynamics and how this specific environment fits into the greater Earth system.

Links

The Crevasse Zone:  GPS Glacier Surveying on the Juneau Icefield, Alaska - Scott McGee's great website devoted to JIRP surveying efforts.

Surveying the Taku Glacier

By Stephanie Streich

This week, I had the opportunity to take part in two different glacial surveys to better understand the nature and changing characteristics of the Taku Glacier, located in the backyard of Camp-10.

The first surveying activity was the monitoring of the surface elevation of Taku Glacier, to track its pattern of growth and deflation. The monitoring of this part of the icefield has been one of JIRP’s long-running projects, and has contributed to a thorough record of this section of the ice.  On this occasion, German surveyor Christian Hein and I traveled by snow machine across Taku Glacier to the same locations that are measured every year with a global positioning system (GPS). Upon reaching the approximate location of each waypoint, while carrying the GPS receiver, antenna and data logger, I walked around the snow machine to find the exact coordinates of the waypoints. Once the points were found, an elevation could be determined by holding the GPS antenna a fixed distance above the ground. This continued throughout the day until all the data for the waypoints were collected (approximately 40). Not only did I learn about the techniques used in the surveying, I was able to appreciate the tedious process of maintaining a record of the health of a glacier. On another note, I was surrounded by a gorgeous landscape that I do not have the privilege of seeing in my every day life, at the University of Alberta.

On my second day of surveying, I went out on the icefield with my former University of Alberta professor, Jeff Kavanaugh, and University of Alaska Southeast professor Jason Amundson to undertake the fieldwork required to monitor the movement of an area of glacial ice on the Taku. During this time, we set up a grid of predetermined GPS coordinates with nine wooden stakes that were jammed into the snow. Once the grid was established, a GPS  antenna was placed on each of the stakes for a half hour to procure their exact locations. The height of the poles were also measured to monitor the rates of snow ablation, or melt.  Jeff intends to revisit these sites two more times before we leave Camp 10 to obtain their GPS coordinates to eventually calculate the surface velocities of the moving ice.

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Stephanie Streich by a GPS antenna, mounted to one of the strain gauge stakes. Photo by Jeff Kavanaugh.

As a student that had not done much field work in the past, participating in JIRP has made me appreciate working in the field in a way that I did not value in school. In a university setting, I learned about field work through the presentations from my professors and in my labs. However, learning about fieldwork and actually applying it in real life are two different things. For example, the presentations that Jeff delivered in class did not come near to actually experiencing what he does as a professional.  In class, field work felt like a strict, rigid, process, which  can be attributed to the stressful environment of university academia. Instead, I was pleasantly surprised to find out  through experience that the work I was doing with Jeff was fun, insightful, relaxed and made me want to know the results of our tests. This is a message that I want to stress: that without participating in JIRP, I may never have known that science does not have to be a rigorous, structured activity in a stressful academic environment. I had lots of fun during my two field trips and hope to do more as the program continues into August.

Glaciers 101

By Grayson Carlile

Since our arrival at Camp 10 we have shifted gears from safety and expedition training to science . Our time has been spent developing our individual research projects and receiving lectures from an exceptional group of faculty. We are beginning to delve into the details of how the icefield functions.

So before we begin filling the blog with our research and theirs, we thought it appropriate to give a brief explanation of what a glacier is - how snow is transformed into the spectacular rivers of ice that we are wandering among this summer.

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The rivers of ice we know as glaciers form from the accumulation of enormous quantities of snow.  Mendenhall Glacier, Alaska.  Photo by Adam Taylor

It all starts with the same snow you might have falling in your backyard during the winter. Most of us, however, do not have glaciers in our backyards, so there must be a few other criteria. Here is where snow quantity and local climate come into play. There has to be enough snowfall that summer temperatures will not melt it all away before the snow returns. Some of the snow that has accumulated has to persist through the entire year.

Then the process has to repeat itself...over, and over, and over again. As time goes on, individual snowflakes begin to metamorphose – their delicate, spindly structures gradually breaking down through a combination of melting, refreezing, and pressure from overlying snow. The resulting products are rounded ice granules called

firn. In the final step on the journey to becoming glacial ice, these firn granules meld into larger ice crystals that fit together like pieces in a three dimensional jigsaw puzzle.

The transformation of snow to glacial ice can take decades to centuries depending on the consistency (wet or dry) and quantity of snow that falls. Once the ice has formed, it can begin to take on the properties of a glacier. As mentioned above, glaciers are rivers of ice. By definition they are moving - pulled downhill by the force of gravity. So in order for the ice to become a glacier, something has to change within the ice in order for it to flow.

Once the ice is a few tens of meters thick, there is enough stress on the underlying ice that it begins to behave viscously - that is, similar to a fluid - and can finally deform and flow. To understand how this works, imagine a ball of silly putty. If you work it in your hands, applying pressure, you can get it to start stretching and slowly flowing. This is essentially what happens to the underlying ice in the 70 meters of accumulation. The pressure of the overlying ice brings it to a consistency that allows it to flow. Once it has reached this point, it begins to succumb to the force of gravity and flow down a valley or across a continent. In addition to this viscous flow, some glaciers such as those that exist in warmer climates, may also flow over the bedrock or sediments at their bases.

So while a reference to glaciers may conjure images of the Arctic or Antarctica in the minds of many, with the right conditions glaciers can form almost anywhere – from the summit of Mt. Kilimanjaro in Africa, to the South Island of New Zealand, to the Cascade volcanoes of Washington State. However, glaciers can and do behave differently in these various locations. Some places, such as Southeast Alaska, where precipitation and cool temperatures are widespread and rampant, cater to more than just a single glacier, producing complex networks of glaciers such as the Juneau Icefield. Here the Coast Mountains receive more snow than almost any other place on Earth. The vast distribution of enormous quantities of snow has created nearly 1500 square miles of glaciated terrain that drains the rugged mountains – flowing east into British Columbia and west into the salty waters of Alaska’s Inside Passage.