scientist post – Lindsay in the Arctic

Post from a Scientist: An Unusual Vacation

Do you have a favorite place to go on vacation? Well, I do, and it’s a bit unconventional. I have spent almost a half a year of my life living in Antarctica! I lived on the Whillans Ice Stream, working hard researching the ice sheet there.

First, let me tell you about Antarctica. It’s a huge continent covered in thousands of feet of ice that accumulated as snow over many thousands of years. Did you know that ice flows (despite how solid it looks floating in your glass of iced tea)? This means that the huge pile of ice sitting on top of Antarctica is slowly flowing under its own weight towards the ocean, where it will break off into icebergs or melt into the ocean. How thick the ice sheet is depends on the balance between how much snow accumulates, and how much ice breaks off or melts into the ocean. If more ice breaks off or melts into the ocean than accumulates as snow, the ice sheet shrinks and sea level rises. If more snow accumulates, then the ice sheet grows, and sea level drops. So if you live near the beach (my other favorite place to go on vacation) and want to know how much sea level will rise in the next 50 years, you need to understand how the ice flows downhill towards the ocean. That’s what I’m studying.

What is an ice stream? An ice stream is essentially a glacier, but instead of flowing between rocky mountains like a glacier in the Alps, it is held on either side by more ice. The ice on either side barely creeps along, moving very slowly, while the ice in the middle flows really fast (1000 feet or more per year). In between the stationary ice and the moving ice, there are house-swallowing crevasses, or cracks in the ice (don’t go there!). Nobody is quite sure what is underneath, but it’s some mixture of mud, sand, water, and rock. Ice streams drain a huge portion of the interior of the Antarctic Ice Sheet.

The Whillans Ice Stream is one of five ice streams on the Siple Coast of West Antarctica, across the Ross Ice Shelf from McMurdo Station. This motley bunch of ice streams has some interesting behavior. MacAyeal, Bindschadler, and Mercer Ice Streams all behave “normally,” flowing out of the highlands of the West Antarctic Ice Sheet and into the Ross Ice Shelf. The Whillans is actually slowing down, and moves in fits and starts. And the Kamb Ice Stream is stopped entirely! How do you stop a river of ice??? (I wish I knew.)

When glaciers and ice streams move, they are sometimes deforming internally (like silly putty), sometimes they slide over their muddy beds, and sometimes they scrape along over harder bedrock. Each of these different kinds of interactions causes the ice to move slow, fast, or unpredictably. The Whillans ice stream falls into the “unpredictable” category. Most of the time, the Whillans is creeping along very slowly. But then, once or twice a day, in step with the tides beneath the Ross Ice Shelf, it suddenly lurches forward, moving a foot or two over fifteen or twenty minutes. Ok, not that exciting, only two feet?? Well, no other ice stream acts like this, so call me crazy, but I find it fascinating. Is this how you stop a river of ice?

Turns out, there are lots of tiny earthquakes (very very very tiny) that occur in certain “sticky” places at the bottom of the ice whileit lurches forward. So this river of ice is slowing down and scraping along the bottom while it does so. Could this be related to what’s causing the ice stream to slow down?

Last year, as part of the WISSARD project, I put a bunch of seismometers (usually used to measure earthquakes) out on the Whillans Ice Stream to study these tiny earthquakes that occur between the ice stream and its bed. My team drilled four holes deep into the ice to put seismometers as close as possible to these little earthquakes. I also have eighteen seismometers and twelve GPS on the surface of the ice, which will allow me to find where the tiny earthquakes are occurring, how big they are, and how the ice stream moves in response. Essentially, I’m using seismometers and GPS to “listen to” and “watch” the ice as it moves over its bed, which might help me figure out what’s so special about the ice stream bed in the stickiest parts of the Whillans Ice Stream story.

Some vacation, huh?

– Grace, University of California Santa Cruz, USA

Post from a Scientist: The Beauty of Things

Have you ever seen a photo of a glacier (or seen one in person) and thought “wow that is beautiful”? I know I have, and that’s exactly why I became a geologist. But there’s so much more to these giant rivers of ice – there a lot that we still don’t know about how Earth’s ice will respond to climate change, and also how changes in the ice itself will affect the climate.

Glaciers in both Greenland and Antarctica move ice from the ice sheets to the oceans, where icebergs break apart and float into the open water. Changes in the water temperature where the glaciers end up can also alter the speed with which these glaciers move ice from one point to another. But scientists are still uncertain exactly how changes in the ocean temperatures can affect these glaciers.

We need to know more about how these glaciers and the oceans interact. As a student in this Glaciology Summer School, I hope to better understand the physics of glaciers and how we can make better measurements, so that we can understand how things are changing and why – in particular, how these conditions affect the future of the ice sheets.

These glaciers do have a big impact on the ice sheets and the whole Earth. They are powerful forces, and that is what I find so beautiful.

– Denis, University of Texas Austin, USA

Post from a Scientist: Cascading Ice

mini-SAM_2479 — Shorts on an Alaskan glacier

In Oregon, where I grew up, agriculture thrives in part because of seasonal snow storage in the Cascade Mountains, which melts into the river system in late spring and summer and provides water during the portion of the year when there’s little rain in the valley. The Willamette Valley, which is on the western side of the Cascades, is also extremely fertile due to the sediment deposits left behind by glaciers that were present in the region thousands of years ago. The region I am studying for my PhD research is the Karakoram and Himalayan Mountains in Asia, which, like the Cascade Mountains, store water for future use. Hundreds of millions of people in India, China, Pakistan, and Nepal live downstream of the Karakoram and Himalayan Mountains and rely on water from the mountains for most aspects of life.

The Karakoram and Himalayan Mountains are extremely steep and contain many of the highest peaks in the world. The Karakoram and Himalaya Mountains have many more glaciers than the Cascades, which have been storing water for thousands of years. In addition to being a natural reservoir of water, the glacial sediment mixed into the glacier melt water helps fertilize the downstream agriculture.

Climate change is affecting both the seasonal snow storage and the longer-term storage by the glaciers. So far in my research, I’ve focused on modeling projections of future snowfall in the regions, and have found that annual snowfall in the region may decrease by 20 to 50%, depending on how much the climate changes. These changes in snowfall are caused by increases in temperature and changes to precipitation, which will also impact glacier mass in the region. My future work will be to model projected changes to the glaciers, then combine this with the snowfall projections and other important hydrological processes, to model climate change affects on river water availability.

Any significant changes to the water availability in this region will be potentially disruptive for the hundreds of millions of people living downstream. By understanding these changes before they happen, we can work to minimize the drivers behind the changes and mitigate the impacts of them. Through this understanding and preparation for the likely changes, hopefully all of us – the people living downstream of the Karakoram, Himalaya, and Cascade Mountains – can continue to have plentiful water resources and glean all the other benefits of having healthy glaciers.

– Thomas, Oregon State University, USA

Post from a Scientist: Things that Melt Out of a Glacier

My first experience working on a glacier in the Canadian Arctic took place on Axel Heiberg Island, in Nunavut Territory. I realize that White Glacier isn’t the most exciting name for a glacier – in this case, a 14 km river of ice flowing from 1800 meters at the highest peaks to nearly sea level – but it is certainly an exciting and beautiful place to work! For thousands of years, precipitation has fallen as snow high in the mountains surrounding White Glacier, and this accumulation of snow builds over the years when the temperature remains cold and below zero due to the high elevation. Over time, the snow is compressed into ice and eventually flows down the mountains through valleys that act as channels for the ice. At lower elevations in the valleys, the temperature is warmer and the ice melts, forming long braiding streams in front of the glacier that eventually flow to the ocean, thereby contributing to global sea level rise. This is the story of a glacier: grow with snow, shrink with melt.

As a 3rd year PhD student (that’s like grade 20!) my science project is to study changes to White Glacier due to the imbalance between the amount of ice gained from snowfall, and ice lost due to melt. Over the past two decades, White Glacier has mainly shown that it loses ice every year, and in 2012 it lost the most ice in any year on record. White Glacier is one of only 5 glaciers in the Canadian Arctic that is studied in this way in order to tell us how Arctic glaciers are responding to climate change. This work is part of a long-term program that was started in 1959 by a group of researchers that founded the McGill Arctic Research Station.

Working at a historic research station has been really interesting. We have a museum of old corned beef cans from the 1960s, and I often find artifacts melting out of the glacier, including old weather instruments, tools for measuring the temperature of the ice, old sleds and skis, bamboo poles for measuring ice melt, and even a pair of wooly socks! It makes me realize how far we’ve come in terms of technology, and at the same time how similar our techniques still are.

– Laura, University of Ottawa, Canada

Post from a Scientist: Himalayan Glaciers

Wow! When I was a kid and hiking on Sundays with my parents – I always marvelled at the landscape and especially at the mountains…and often I was left behind. 🙂 From then, I wanted to discover the world and wanted to know why things are how they are. And this is what I do today.

I’m Patricia and I am a PhD candidate at the University of Potsdam in Germany. I finished my Masters in Earth Sciences in 2011 at the Federal Institute of Technology in Zurich (Switzerland). My focus area of interest is the influence and interplay of tectonic processes and climate (precipitation, glaciers) on landscape evolution. During my Masters I therefore mainly focused on geology (structural geology, sedimentology, paleoclimatology). My current PhD project, called “Competing influence of glacial and fluvial erosion in the NW Himalaya, India” still covers some of these aspects. It focuses on exhumation of bedrock to the surface in the northwest Himalayas, and if this is influenced by climate or tectonics. This part of the Himalayas is still glaciated and influenced by rain and snow, but also by glaciers. The complexity of the interplay of the climate and tectonic processes makes it to an interesting area of study. Apart from learning new geo-chronological methods, I also “slipped” into the field of glaciology, which so far I have only just touched on. I want to know if glaciers, in the interplay between regional tectonics and climate, are able to impede or accelerate erosion?

In the Himalayas, glaciers are important for humans as they store freshwater for an entire region. But the retreat of glaciers does not only influence water availability. It can also cause devastation due to glacial lake outbursts, which can affect agriculture. Reading the landscape to reconstruct former glacial stages and the consequences of glacial retreat, as well as the prediction of future events, may help people in the region to prevent more damage.

In my research, different aspects are taken into account when you discuss results. On the one hand, long term evolution hardly affects people in the short term, but is very interesting. On the other hand, climate questions are certainly related to glacial and interglacial cycles. Glaciology can help us to understand these patterns better. At this summer school, my aim is to enhance my knowledge and understanding of the glacial system, so that I am able to describe and explain observations I made in my field.

– Patricia, University of Potsdam, Germany

Post from a Scientist: The Climate Crystal Ball

Have you ever looked at a landscape and thought to yourself… How did this happen?! … Why is this hill here? … Why do these rocks look like this? … What does it all mean?

My job is to look for clues in the landscape that indicate the former presence of glaciers. Glaciers are masses of ice that flow downhill from mountain tops, where it is cold enough for snow to remain on the ground all year round. Rocks fall on the surface of glaciers and are transported to the glacier margins where they accumulate in elongated, sharp-crested ridges (as in the photo). These ridges are called moraines, and they can remain in the landscape long after the ice melts away. When I find moraines in a location where no glaciers currently exist, I ask myself these questions: (1) Why did a glacier used to be here? (2) When was it here? (3) Why is it no longer here?

I am here at a glaciology summer school in Alaska, USA, to learn about what causes glaciers to grow and shrink. Temperature is a key control as it determines how much precipitation falls as snow rather than rain in winter, as well as how much snow and ice melts in summer. When temperatures remain stable for a many years, glaciers eventually reach an equilibrium state, where input of snow equals output by melt, and the glacier length remains stable. If temperatures increase, then less snow may fall and/or more melt may occur, causing the glacier to retreat. If temperatures decrease, then more snow may fall and/or less melt may occur, causing the glacier to advance. As moraines represent former glacier lengths, they contain important information about past climate change.

My research focuses on two volcanoes in central North Island, New Zealand – a long, long way from Alaska! I have multiple moraines in several catchments on these volcanoes, which document former glacier length changes. I have dated these moraines using a technique known as “cosmogenic surface exposure dating.” This technique measures the accumulation of rare elements, produced by exposure to high-energy particles that come from outside our solar system and reach the Earth surface. The moraines on these volcanoes range in age from 200 to 60,000 years old. Now I am using a computer model that simulates the growth of glaciers under different climatic conditions. I input different temperatures to try to recreate the former glacier lengths, as indicated by the moraines I have found. Putting the moraine ages and model results together, I end up with estimates of how much colder it must have been in New Zealand at a certain point in time.

I know what you’re thinking … you’re thinking “who cares how cold it was thousands of years ago?” Well, that’s a great question. These results are important for several reasons. For example, they provide an important test for computer models that try to predict future climate change. If these models can recreate past changes, then we have increased confidence in their predictions for the future. You can think of this as cleaning the climatic crystal ball, making it easier to look into the future and see what Earth’s climate may be like for your children and grandchildren.

– Shaun, Victoria University of Wellington, New Zealand

mini-blog_Shaun — Here I am on a moraine at the side of a former glacial valley that drains away from the active volcanic cone of Mt. Ngauruhoe in New Zealand.

Post from a Scientist: Water Slides!

mini-SAM_2624 — On the edge of a glacier

Can you imagine a continent as big as the United States covered with ice more than four times as thick as the tallest building you have ever seen? If that is hard for you to picture, you are in the same boat as I was when I decided I was interested in glaciology. It was my curiosity as to how things as large as the massive ice sheets covering Greenland and Antarctica can move and rapidly change, that made me want to study glaciers. Knowing that through sea level rise these changes would affect people throughout the globe, perhaps even within our lifetimes, is the little bit of connection to something closer to home that continues to motivate my work.

One of the biggest surprises to me when I started in glaciology was the ease, using satellites, with which we can get information about the way the surfaces of the ice sheets are changing. On the other hand, there are very basic things that we understand fairly poorly about both the basic physics of how ice flows and about things which take place underneath the ice. For example, ice is pretty easy to look through if it is small, like an ice cube in a glass, but when it gets thick and full of bubbles you cannot see all the way through, like ice on many lakes in winter. We have some tools to overcome problems like these, but basic things like the height of the land underneath the ice sheets is something that is difficult to measure, and we do not know very finely.

My research tries to take advantage of the recent data that are available for one particular group of glaciers in Antarctica. I use these data to understand how these glaciers change and to try to gain insight into some of the processes in the ice which are not directly observable. I’m especially interested in how other earth systems – the ocean and atmosphere in particular – affect how the ice sheets evolve. Melting driven by the warm ocean causes rapid thinning where ice from the continent meets the ocean, and the flow of the ice is very sensitive to these changes. I try to better understand how small changes in melt will affect how things change on a larger scale. In some ways this is like coming down a waterslide into a pool. If there is more water, you will slide faster. If you arch your back so you scrape against the slide less, you will move more quickly. My research is like trying to figure out, depending on much water there is and what part of you is touching the slide, when you will splash into the pool and cause the water level to rise.

– David, University of Washington, Seattle, USA

Post from a Scientist: How Not to Get Lost on a Glacier

Have you ever used a compass to find your way through unfamiliar territory? Did you know that some thirty thousand years ago the compass needle would have pointed in the opposite direction? Yes, indeed, there have been times in the history of the Earth during which the north and south poles of the magnetic field were swapped! There is a complex set of mathematical equations – called partial differential equations, to be precise – that is thought to describe how the magnetic field is actually generated. The mathematical object that scientists believe is “responsible” for the reversal of the poles is called a heteroclinic cycle. Technically speaking, this cycle consists of several steady states (where the magnetic field does not change over time) and the connecting times, when the north and south pole of the magnetic field swap. This kind of stop-and-go dynamics is encountered in many other scientific applications as well, such as modeling the evolution of animal species competing with each other, or communication networks within the human brain.

This variety of applications is why I think it is highly interesting to study this phenomenon from an abstract, mathematical point of view. In particular, I study the stability properties of these heteroclinic cycles. The concept of stability is crucial for distinguishing pure mathematics from what we can actually “see” in real life. For example, think of a ball rolling along a hilly surface. We would never see the ball come to a stop right on the top of a hill – even though math says that is theoretically possible. Even the smallest movement will cause it to move away from the hilltop, and never return. This is a classic example of an “unstable state.” In my research, I am working on finding mathematical conditions for a heteroclinic cycle to be stable rather than unstable, so that we may understand better how the parts influence the systems in which we discover them.

So, next time you’re navigating through the woods with a compass, don’t despair when you get lost – there is a slight chance that it is just the Earth’s magnetic poles swapping positions that keeps you from finding your way…

– Alex, University of Hamburg, Germany

Post from a Scientist: Glacier’s Slippery Shoes

mini-SAM_2319 — Here, it’s possible for you or the glacier to slip.

Dealing with slippery surfaces is perhaps one of the very first physical phenomena that we deal with as kids. It is always challenging to keep your balance, not to fall down, or not to break your bones. Similar to any other kids, I always asked my father why he drives slower on rainy days. The answer was the same to all of these questions. Friction!

Surprisingly, my research ended up being in a similar realm. Ice sits on the solid ground, a massive 2-3km thick cold block. But that poor block also suffers from the same imbalance that I had as a kid as my shoes slipped on the ground where I was walking when the ground was wet. That’s right, the block slides faster, just like me. It goes down the slope where it is sitting, and falls into the ocean. That’s why we want to know if the glacier’s “shoes” are wet or not!

A large number of physical sciences come together and help develop tools like satellites, in-the-field measurement techniques, and computer models, so that we can estimate the temperature at the bottom of the ice sheet. This way I can see whether the ice sheet and I are sharing the same slippery experience!

– Soroush, University of Kansas, USA

Post from a Scientist: Tropical Ice Caps

When I think of the tropics, I usually think of brightly-colored fish and palm trees. More recently, I also think about glaciers, which are not only in the polar regions, but also sometimes in the tropics as well. But as a warning, I wouldn’t plan my family vacation there – glaciers are on very high and remote mountains! Today, when I think of the tropics, I try to imagine what will happen to these glaciers in the future, and to help me, I use computer models to try to understand how these glaciers grow and shrink with climate change.

Glaciers grow and shrink depending on whether the long-term weather is colder versus warmer, or snowy versus less snowy. Imagine a see-saw at a playground. On one side are things that make glaciers grow, such as colder temperatures and snowy weather. On the other side are things that make glaciers shrink, such as warmer temperatures and less snowy weather. I use my computer models to figure out how changes in temperature and snowfall will affect each side of that see-saw, and whether the changes in tropical glaciers will be the same as or different from the changes in glaciers in higher latitudes, such as in the Rocky Mountains, Canada, and Europe.

Thanks to my research, when I think of the tropics, instead of just thinking about tropical fishes, I now think about a tropical ice cap that looks like an upside down frog from space. This is the Quelccaya Ice Cap in the Peruvian Andes, which is the world’s largest tropical ice mass. Since tropical glaciers are so hard to get to, scientists haven’t been able to study them until recently. But a few hundred years ago, the ice cap was larger than it is today, and in my research, I try to figure out how much colder and snowier it was during those times when the ice cap was larger. I have found that the ice cap can become significantly larger only with a slight cooling of temperatures, and that it can become significantly smaller with only a mild warming of temperatures. So next time you think about Miami, I hope you think about beautiful sandy beaches and ocean filled with stunning, colorful fish, but I hope you also think about a frog-shaped tropical ice cap, and wonder how it and other tropical glaciers are changing with global warming.

– Andy, University of Chicago, USA

mini-andy_quelccaya_12km across — The Quelccaya Ice Cap in the Peruvian Andes (see the frog shape?)