Hypotheses

In my undergraduate degree we spent a lot of time studying the history of science and development of the scientific method, and its important to convey some of this to students undertaking independent research projects even if they have not studied it so extensively. Following the scientific method gives the research a clear structure and makes the whole process much easier in the long run!

Here is a decent summary diagram of the whole thing from https://www.sciencebuddies.org/ which appears to be designed to help US students with science fair projects, but is nevertheless totally suitable for my purposes here:

The question might come from an observation, from a previously identified gap in the scientific literature, from your disagreeing with something you read in the literature, or it might even arrive while you are brushing your teeth (so I’m told).

One aspect of this procedure that seems to pose difficulties is constructing a testable hypothesis. There are of course some research questions for which it is easier or harder to devise a testable hypothesis but its important, prevents bias in your research, and makes the whole process cleaner and easier to actually execute. A hypothesis is a statement, not a question. Your hypothesis is not the scientific question in your project. The hypothesis is an educated, testable prediction about what will happen, and its important to establish the hypothesis before you start the experiments or data analysis tests as these should be designed to test the hypothesis.

So, the key is that before we set out to answer the research question by performing an experiment and observing what happens, we first clearly identify what we “think” will happen in response to a given set of circumstances.

  • We make an “educated guess” about what we expect to happen
  • We write a hypothesis from this
  • We set out to disprove the hypothesis using specifically designed tests/experiments/analyses

Here are some examples of good, poor and bad hypothesis, also from Science Buddies

Here is a more in-depth blog from Bethan Davies about designing good academic research studies for students: http://www.antarcticglaciers.org/students-3/postgraduate-students/research-design/

And the accompanying seminar that Bethan gave as part of the Association of Polar Early Career Scientists (APECS) webinars (skip to minute 2 where it starts for real):

Bethan also has a useful blog post with more practical advise for completing a BSc or MSc dissertation or thesis: http://www.antarcticglaciers.org/students-3/writing-your-dissertation/

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Are the snows of Greenland pristine or polluted?

I recently prepared a blog for Der Standard an Austrian newspaper entitled: Wie unberührt ist Grönlands Schnee? I say prepared as really it was re-written by my colleague Elisabeth Schlosser to make the German sound more native!

Anyway here is an English version of it:

Nowadays my work is primarily studying glaciers, but I used to work in a water chemistry laboratory, studying ice cores from the Canadian Arctic.

An ice core section showing dust layering inside it. Photo B. Markle

I always liked how clearly you can see the impacts of some human activities in ice cores,  for example by looking at the lead records you can see the rise of leaded petrol use in the 1920s, and then the subsequent advent of unleaded petrol from the mid-1970s to the early 2000s.

Measured lead (Pb) levels in an ice core from Greenland (annual samples) and the Monte Rosa massif (5-year samples) in the Alps. Lead can come from a variety of sources but you can see the pattern of leaded and unleaded petrol usage. Graphic redrawn from Osterberg et al, 2008; Greenland data from McConnell et al (2006) and Alpine data from Schwikowski et al (2004).

Although the levels of lead measured in the ice core from the European Alps are much higher, the pattern of leaded petrol use can also be seen in the Arctic areas even though most of the industrial activities and cars are far away from the Arctic.  This is because the snow falling in the Arctic is made of moisture that has travelled far through the atmosphere and so it carries the emissions and pollutants from elsewhere into the Arctic. Thus, some of the impacts of our activities in mainland Europe are felt in the farthest reaches of our planet.

A family of pollutants that is of particular interest in the Arctic are the so-called persistent organic pollutants (POPs). POPs are man-made compounds like pesticides, herbicides and fire retardants that are not easily broken down in nature. Because of being so long-lived, they can be transported far from their place of emission or use into the Arctic, where they are stored in snow, water and soil. Unfortunately these POPs are generally toxic, and have been found in elevated concentrations in the fatty tissue of Arctic fish, seabirds, whales, polar bear and human populations. POPs may be responsible for long-term health issues, in both animal and human populations, including hormone disruption, infertility and cancer.

Last year I was asked to participate in an expedition called POP Greenland to collect samples of snow from Greenland to see how much POPs are being transported into the Greenlandic snow. We will use non-contaminating sampling techniques to collect large samples of fresh snow, which will later be analysed to find out the concentration of pollutants within it.

Agna and I learning how to take snow samples in the field and Krys in the laboratory.

We were hoping to traverse the icesheet taking regular samples but the logistics for that did not work out, so now we are sampling at two locations in east Greenland and we have linked up with colleagues from the Greenlandic Geological Survey, the Norwegian Polar Institute and students from the Royal Scottish Geographical Society Polar Academy, who will take samples from other locations on Greenland to spread the reach of our study.

Once we have found out the current levels of modern POPs in the snow, we will use 3D representations of air flow from atmospheric models to trace their transport pathways back to the likely location of the source emission. By doing all this, we can develop a much better idea of the present deposition and storage of POPs in the snow and ice of the Greenland icesheet.

Knowing the modern day levels and transport pathways better will also enable us to make a more educated estimate of how much pollution was deposited in the Greenland snows since the start of the 20th century.  This is important because, during the middle of the last century, much higher levels of more toxic, pesticides and other POPs were used. The Stockholm Convention which has been in effect since 2004 restricted use of 12 of the substances deemed most potentially damaging. However, meltwater runoff from the icesheet is coming from both modern and older snow and ice, and this will flow into the rivers and surrounding ocean. Our work will help us find out if, counterintuitively, meltwater from the seemingly ‘pristine’ Greenland icesheet may in fact present a source of toxic pollution to the Arctic environment in the coming years.

In case you are wondering, the sampling team is being kept as small as possible, and we will do our sampling by ski to minimise the use of vehicles in Greenland. To get there, from Austria and Poland, we do however have to use planes and helicopters. As far as possible the carbon emissions of this travel have been offset, but we know it is not perfect.

Our project is supported primarily by a National Geographic Society Explorers Grant. You can follow our project on the web (www.popgreenland.wordpress.com/) and via social media (@POP_Greenland or www.facebook.com/popgreenland/). Agna and Justyna set off for Greenland on April 10th – I will join them on May 15th.

If you are really interested in this topic the Arctic AMAP report is a great source of information: https://www.amap.no/

  • Osterberg, E. C., Mayewski, P., Kreutz, K., Fisher, D., Handley, M., Sneed, S., Zdanowicz, C., Zheng, J., Demuth, M., Waskiewicz, M. and Bourgeois, J. (2006) Ice core record of rising lead pollution in the North Pacific atmosphere, Geophys. Res. Lett., 35(5), 2–5.
  • McConnell, J. R., S. Kipfstuhl, and H. Fischer (2006), The NGT and PARCA shallow ice core arrays in Greenland: A brief overview, PAGES Newsl., 14, 13– 14.
  • Schwikowski, M., et al. (2004), Post-17th-century changes of European lead emissions recorded in high-altitude alpine snow and ice, Sci. Technol., 38, 957– 964.
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Crevasse rescue training

Every year as we take a new bunch of student helpers out to the glaciers with us we arrange a crevasse rescue course. This year Benjamin and Christoph Stern were our guides at the Stubai Gletscher ski area where we slid down steep faces to be rescued s part of a larger rope team and practiced rescuing conscious people on a smaller 3 person rope team. Then we went to the stairs to practice self rescue:

I love doing these courses every year as I always learn something new, or refine my skills or get another idea of something to think about while undertaking glacier travel. There is much that i already feel quite adept at – judging the landscape, assessing dangers, setting anchors of various kinds, direct haul rescuing using a z-pulley system, self rescue, but, for example, this was the first year I ever practiced a rescue with a larger rope team (as we usually travel with just 2-3 people for fieldwork), and we also discussed how dangerous it can be to leave someone hanging unconscious in a crevasse and how to get to them fast and rig a little chest harness to get them into a stable position. I practiced using the Garda hitch which is nice, as although I usually have a Petzl microtraxion with me, you never know when you might have to work without it. Especially when you are ham-fisted like me, and likely to drop valuable gear into crevasses …

Stay safe out there!

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Life on ice and bioalbedo

Birgit Sattler is a biologist here in Innsbruck studying the microbial life of Alpine glaciers with her team in a project called Black Ice. I’m trying to help them out a bit by running our massive freezer room for some experiments on the growth of algae in the Hintertux glacier show caves … but so far the pesky device has failed us and cooked the samples instead. Anyway here is their teaser for the Black Ice project:

Microbial life on glaciers is a pretty hot topic these days with numerous activities on Greenland such as the Black and Bloom project and well-publicized work by researchers such as Arwyn Edwards and Joseph Cook and colleagues.

Here is Joseph Cooks video about his work as a Rolex Award for Enterprise Laureate:

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Polya’s Problem Solving Techniques

Teaching University students to carry out critical and independent science research is challenging, and they need to learn to flex new muscles and approaches in their brain, that are not always well stretched at the school stage. I have found the summary of George Polyas lessons that I reproduce below on a number of websites (e.g. here) and I do not know the original source, but its great – have a read:

In 1945 George Polya published a book How To Solve It, which quickly became his most prized publication. It sold over one million copies and has been translated into 17 languages. In this book he identifies four basic principles of problem solving.

Polya’s First Principle: Understand the Problem

This seems so obvious that it is often not even mentioned, yet students are often stymied in their efforts to solve problems simply because they don’t understand it fully, or even in part. Polya taught teachers to ask students questions such as:

  • Do you understand all the words used in stating the problem?
  • What are you asked to find or show?
  • Can you restate the problem in your own words?
  • Can you think of a picture or diagram that might help you understand the problem?
  • Is there enough information to enable you to find a solution?

Polya’s Second Principle: Devise a Plan

Polya mentions that there are many reasonable ways to solve problems. The skill at choosing an appropriate strategy is best learned by solving many problems. You will find choosing a strategy increasingly easy. A partial list of strategies is included:

  • Guess and check
  • Look for a pattern
  • Make an orderly list
  • Draw a picture
  • Eliminate the possibilities
  • Solve a simpler problem
  • Use symmetry
  • Use a model
  • Consider special cases
  • Work backwards
  • Use direct reasoning
  • Use a formula
  • Solve an equation
  • Be ingenious

Polya’s Third Principle: Carry Out the Plan

This step is usually easier than devising the plan. In general, all you need is care and patience, given that you have the necessary skills. Persist with the plan that you have chosen. If it continues not to work, discard it and  choose another. Don’t be misled, this is how things are done, even by professionals.

Polya’s Fourth Principle: Look Back

Polya mentions that much can be gained by taking the time to reflect and look back at what you have done, what worked, and what didn’t. Doing this will enable you to predict what strategy to use to solve future problems.

These principles and more details about strategies of carrying them out are summarized in this document:Polya’s Problem Solving Techniques

George Polya (1887–1985) was one of the most influential mathematicians of the twentieth century. His basic research contributions span complex analysis, mathematical physics, probability theory, geometry, and combinatorics. He was a teacher par excellence who maintained a strong interest in pedagogical matters throughout his long career. Even after his retirement from Stanford University in 1953, he continued to lead an active mathematical life. He taught his final course, on combinatorics, at the age of ninety.

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Landlab teaching tools

I’m trying to develop teaching materials using Jupyter notebook (mainly inspired by my colleague Fabien Maussian) and its super interesting but quite hard work for me as a python beginner. I was looking for other things people have been doing with this format and I came across the teaching tools that accompany Landlab, which aims to create an environment in which scientists can build a numerical landscape model without having to code all of the individual components (Hobley et al., 2017). Landscape models have a number of commonalities, such as operating on a grid of points and routing material across the grid. Scientists who want to use a landscape model often build their own unique model from the ground up, re-coding the basic building blocks of their landscape model rather than taking advantage of codes that have already been written. Landlab offers python coded building blocks for developing your own model. Cool huh? Landlab is described in an open source paper.

The Landlab team currently shares teaching resources appropriate for geomorphology and surface water hydrology classes. The exercises use numerical models to illustrate physical processes. These exercises were designed as homework or laboratory assignments, but they could also be used to illustrate concepts in the classroom related to:

  • Hillslopes evolving according to the linear diffusion equation.
  • Drainage density sensitivity to the strength of hillslope and fluvial processes.
  • Fluvial channel morphology (steepness and chi-elevation relationships) sensitivity to rock uplift and rock erodibility.
  • Hydrograph sensitivity to watershed shape and storm characteristics.

These exercises do not require coding knowledge. They are written in Jupyter notebooks, which combine text and code, and are easy for students to use. The exercises include directed exploration exercises (i.e. students are told exactly how to change the code and run it) and thought and interpretation questions based on the resulting plots. The exercises can be tailored for your class.

Everything is open source so FREE! You can even run them online without any software installation.

For more information: https://github.com/landlab/landlab_teaching_tools (scroll down that page to see text), or just email the developer: Nicole Gasparini ngaspari@tulane.edu

References:

Hobley, D. E. J., Adams, J. M., Nudurupati, S. S., Hutton, E. W. H., Gasparini, N. M., Istanbulluoglu, E., and Tucker, G. E.: Creative computing with Landlab: an open-source toolkit for building, coupling, and exploring two-dimensional numerical models of Earth-surface dynamics, Earth Surf. Dynam., 5, 21-46, https://doi.org/10.5194/esurf-5-21-2017, 2017.
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Der Standard “Eis und Klima” blog

Our research group has started blogging on Der Standard, an Austrian broadsheet. The aim is to let Austrian readers know a bit more about both our research, why we do it, and what is involved in being a working scientist.

Part of the idea is to offset the (for me a bit upsetting) trend of doubting scientists and their motives for doing their work, by showing a bit of ourselves in this blogging process, while also letting people know what is being done with our portion of the Austrian research funds we are allocated.

Hopefully it will be a positive experience, though it means I need to write a blog post in German, which will be an ugly process no doubt. So far only two of us has posted, but watch out for more to come, we aim to post every 4-6 weeks.

Kristin Richter has posted on Die Vermessung des Meeresspiegels (Measuring sea level), starting with the question of how come an oceanographer studying sea level rise ends up in the Alps, and going on to explain what data on sea level rise is available for investigations.

 

Johannes Horak has posted on Die Vermessung der Gletscher (Measuring glaciers), covering a broad sweep of what glaciers are, some reasons why they matter, how they are changing and how we can measure these changes.

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3D numerical model of englacial transport

Anna Wirbels first PhD paper is out, and downloadable from my publications page (Wirbel et al., 2018). What she has done is take an existing freely available 3D model of ice flow (icetools; Jarosch et al., 2008) that employs the full Stokes equations to describe the flow of ice. This type of numerical treatment of ice flow offers the most realistic representation of the flow of complex mountain glaciers, assuming adequate inputs, such as terrain properties and ice temperatures are well known.

Anna worked, with guidance from Alex, to introduce a numerically robust, mass conserving, treatment of advection of deformable inclusions within this ice flow field. This allows her to represent englacial debris transport – illustrated in the video below by artificially imposing layers of initially circular inclusions into a cross-section of a glacier with fixed geometry and flow field (Time is in years):

Isn’t that cool?! (The full resolution video is downloadable as supplementary material to the publication)

Imagine the initial circular feature as a lump of rock material from a rockfall that has been buried in the accumulation zone, or sediment trapped in a hollow in an englacial channel, imagine the initial surface layer as an ashfall, and the initially vertical bands part way down the glacier as rocks and detritus that has fallen into crevasses, then look how over time they all get deformed and elongated into bands, which is what we see in real glaciers!

Also, notice how over time, even in this fixed flow field case, the location of debris emergence and the angle of incidence of the debris band with the surface both change over time. In these cases the model does not keep track of the debris once it emerges to the glacier surface, but its clear that both of these aspects will affect the debris flux to the glacier surface, and, combined with the surface ablation will determine the manner in which a supraglacial debris cover forms.

The model code is available from Anna on github: https://github.com/awirbel/debadvect/releases/tag/v1.0.0

References:

Jarosch, A. H. (2008) Icetools: A full Stokes finite element model for glaciers, Computers & Geosciences, 34(8), 1005–1014, doi:10.1016/j.cageo.2007.06.012.

Wirbel, A., Jarosch, A. H. and Nicholson, L. (2018) Modelling debris transport within glaciers by advection in a full-Stokes ice flow model, The Cryosphere, 12, 189-204, https://doi.org/10.5194/tc-12-189-2018.

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Featured on the cover of Geosciences Vol 7, No. 3

Well, a nice surprise at the start of the year: Hannah Prantls paper on mapping glacier snow cover extent and snow line elevation using terrestrial laser scanner signal returns is featured on the cover of Geosciences Vol 7, No. 3. Pretty cool as I think this is Hannahs first research article 🙂

The summary text for the paper is:

We demonstrate that Terrestrial Laser Scanner (TLS) return signals can be used to accurately map the snow cover extent over a glacier. A rule-based classification employing intensity, surface roughness and an associated optical image, achieves classification accuracy of 68–100%. Snow cover extent is valuable information for glacier surface energy balance models, which are sensitive to the glacier surface condition, however as the TLS intensity signal shows no meaningful relationship with surface or bulk snow density, the snow mass remains elusive.

Here is the featured figure:

Evolution of the TLS and AMUNDSEN model snowlines during summer 2014 and summer 2015. The order of the raster layer is: (A) 26 June 2014, (B) 18 July 2014, (C) 1 August 2014, (D) 25 August 2014, (E) 4 September 2014, (F) 23 September 2014, (G) 4 October 2014, (H) 21 April 2015 and (I) 1 October 2015.

And by all means consider reading the whole paper:

Prantl, H., Nicholson, L., Sailer, R., Hanzer, F., Rastner, P. and Juen, I. (2017) Glacier snowline determination from terrestrial laser scanning intensity data, Geosciences, 7, 60, doi:10.3390/geosciences7030060. [pdf]

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Randkluft and bergschrund

I only just found out what a randkluft gap is. For years I’ve been wrongly calling it a bergschrund. I love how these words are readily known by German-speaking mountaineers and I am so late to the game despite it being in my field of study.

Wikipedia sets me straight: “A randkluft is similar to, but not identical with, a bergschrund, which is the place on a high-altitude glacier where the moving ice stream breaks away from the static ice frozen to the rock creating a large crevasse. Unlike a randkluft, a bergschrund has two ice walls.” and provides this helpful graphic.

And now I am already know something more in 2018 than I did in 2017. Keep learning, keep growing, so it is said!

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