Lab 20: Alpine Glacial Processes
Crystal Huscroft and Katie Burles
In this lab you will be using your understanding of glacial processes to make observations and measurements documenting and predicting the consequences of climate change for a Canadian alpine glacier. You will learn how to analyze the characteristics of glaciers and glacial landforms from a variety of types and sources of satellite imagery, and then you will have the opportunity to create a guided tour presentation to increase community awareness the impacts of climate change.
After completion of this lab, you will be able to:
- Make observations, identify, and appreciate the consequences of global warming for alpine glaciers.
- Analyze the characteristics of alpine glaciers in order to make predictions regarding the future survival of a glacier.
- Summarize and collate GIS point, line, and area information from different platforms into a single GIS project.
- Acquire and interpret remotely sensed imagery.
- Communicate effectively regarding the impacts of global warming for BC glaciers.
Introduction to Glacial Processes and Landforms
Understanding of the following key terms is required for this laboratory activity.
If you are unfamiliar with any of these terms, look them up before continuing.
|Ablation zone||Equilibrium line||Snowline|
|Annual ice horizon||Glacial ice||Valley glacier|
|Cirque glacier||Glacier toe|
How to Determine Whether a Glacier Will Survive Current Climate
Glaciers form and persist in areas where snow accumulation is consistently greater than snow and ice melt or sublimation (ablation). Glaciers that are in danger of disappearing will show evidence of insufficient snow accumulation to persist through the melt season. As described by Dr. Mauri Pelto on this website (please read) and this paper (Pelto, 2010), the likelihood of a glacier’s survival can be assessed using the following visual clues in remote sensing imagery:
- Newly exposed rock outcrops in the accumulation zone. These rock outcrops may appear lighter than surrounding rock due to a lack of lichen growth on their surface.
- Lowering of the surface and a reduction in size of the upper margins of the glacier. This might also be indicated by light coloured rock margins around the edges of the glacier due to exposure of unvegetated (mostly lichen) rock and debris.
- Discontinuous snow cover in the accumulation zone. This may appear as patches of bare ice surrounded by snow.
- Less a third snow cover over the glacier late in the melt season.
The following video captures a glaciologist, Dr. Mauri Pelto, applying the concepts above and performing the same type of analysis that you are asked to perform in this lab.
Introduction to Sentinel 2 Imagery
In the following lab, you will be analyzing false colour images captured by the Sentinel 2 satellite program. The Sentinel 2 program consists of twin satellites launched by the European Space Agency that are able to capture imagery of Earth at a resolution of 10-60 m. It consistently captures images between 56° S to 84° N every 5 days. Unlike our eyes, the satellite system can detect energy in the visible, near-infrared and shortwave infrared portions of the electromagnetic spectrum.
Although the satellites measure 13 spectral bands of reflected and emitted energy, false colour images using three specific bands of energy are excellent for studying glaciers because they are able to detect and differentiate ice and snow (Bands 11, 8A, 4). In these false colour images, snow and ice appear in separate teal shades of blue and water appears a very dark shade of blue.
In the exercises below, you will be creating a document and a guided virtual tour using a Google Earth (web) presentation regarding the likelihood of a glacier’s survival in the current climate. You will be accessing topographic and satellite information regarding a glacier of your choosing from the following platforms so that you can discuss factors that have affected your glacier’s behaviour in terms of retreat and the likelihood that the glacier will survive current and future warming:
You will create two products from this work: a PDF and a Google Earth presentation in the form of a kml file. You will be guided first to complete the PDF, and then incorporate information into Google Earth.
1. Choose a glacier.
Open Google Earth (web) and familiarize yourself with the navigation controls. Explore the mountainous regions within Canada and choose an alpine glacier somewhere in Canada that you would like to study. Determine its geographic grid coordinates (latitude and longitude) in decimal degrees.
It is best to choose an alpine glacier that is not too snow-covered in the Google Earth (web) imagery so that the margins of the glacier are clearly visible. Cirque glaciers with a single outlet will be less time consuming to map than icefields with multiple outlets.
2. Create an oblique 3D view of the glacier.
Within Google Earth (web), view your glacier in 3D. Tilt your view and navigate to a view of the glacier that gives a good perspective of the shape and steepness of your glacier, and enough of the adjacent topography to give the viewer an idea of the character of adjacent mountains.
Create a screen capture of this view and save it as a JPEG file with a file name in the format <1_lastname_firstname_3D_image>. Your glacier should take up the majority of the center of the photo, so that is obvious as to which glacier you are studying.
3. Create a title slide and introduction (Figure 1).
The image in step 2 will be the image for your title slide in a PDF report and a Google Earth (web) presentation. Paste your image into a document that can later be saved as a PDF. Be sure to set up your document in landscape mode. Write a figure caption in paragraph form that includes the following information:
a. The glacier’s geographic grid coordinates in decimal degrees (latitude and longitude).
b. The direction of view of the image. What direction (north, east, south, west) is the camera looking in the image you attached?
c. The glacier’s name (if applicable). Many Canadian glaciers are not named. You can check if your glacier has a name by visiting the Atlas of Canada – Toporama website. Warning: this site loads slowly. If all you see is a link to GeoGratis, give it a few more moments to load a map.
d. A description of the glacier’s location relative to major landmarks like towns, lakes, highways. For example, “30 km northeast of Pemberton.”
e. The physiographic region the glacier is located within. Depending on the province or territory where you chose your glacier, you will need to refer to the following reports:
f. A description of the main bodies of water that the glacier meltwater feeds. You can see this by tracing the flow of water from the glacier to an ocean using the Atlas of Canada – Toporama website again.
g. A description of why you chose the glacier. This is a short description and there is no wrong answer. Just be honest. Maybe you have seen this glacier, maybe you would like to travel there, or maybe your choice was completely random. If you have your own personal picture of the glacier that you would like to share, please include it as Figure 1b. Your lab instructor would love to see it. You can choose to copyright it or release as Creative Commons by using this copyright builder.
h. A description of the image source. The source of all images used in any report should be described.
Resize the image so that the image and caption for Figure 1 can fit on one page in landscape view (Figure 20.1).
4. Topographic map (Figure 2)
Figure 2 (Figure 20.2) will be a topographic map with a scale bar of your glacier. In order to create the image, within the Atlas of Canada, navigate back to a view of your glacier that captures the entire glacier. Take a screen capture of your image including the scale bar, the contours above and below your glacier, and the north arrow.
Write a caption for your figure that includes the following:
a. The aspect of the glacier (north, east, west, or south-facing).
b. The maximum and minimum elevation of the glacier.
c. Whether or not the glacier originates from a cirque or valley glacier.
d. The image source.
5. Describe the length of the glacier (Figure 3).
In Google Earth (web) start a new project and name it <Lastname Firstname Glacier Survival Lab>. Create a new line feature by digitizing a centerline for the glacier that extends from the approximate center of the upper extremity of the glacier to the lower extremity. Your line should follow the topography downwards. Your line should parallel the glacier flow direction and any downhill sloping debris bands. Name this feature “Glacier length.”
Next, measure the length of this line with the measuring tool (ruler on the left side of your screen). While the value of the length is still displayed in a white box, take a screen capture of this measurement and use the image as Figure 3.
Write a caption that describes the length of the glacier to the nearest 100 m.
6. Identify evidence of Little Ice Age Glacier extent (Figure 4).
In this figure, you will try to depict any evidence of the past maximum extent of your glacier during the Little Ice Age. The Little Ice Age was a period of cool climate when glaciers in Europe and North America advanced from their current positions. The period spanning from 1100 CE to 1850 CE includes several series of advances. The evidence left on the landscape from these advances includes trimlines and moraines that wrapped around the edges and toe of the glacier.
Zoom out from the view of your glacier. Using a green line, trace any features you see that could indicate how far your glacier once extended. If you do not see any indicators of past glacier extents (they may be obscured), you do not need to add any features.
If you did not see any evidence, create a screen capture of a view that supports your assertion that no features are evident. Save this file as <4_Lastname_Little Ice Age>
If you found clues as to prior glacier extents, measure how long the glacier once was. While the value of the measurement is still visible in a white box, create a screen capture and save the file as <4_Lastname_Little Ice Age>.
Write a caption for Figure 4 that indicates the types of clues you used and a measurement of how long the glacier may have extended during the Little Ice Age. If you did not find any clues, write a caption saying so.
7. Capture Google Earth Engine Timelapse imagery (Figures 5 & 6).
Visit the Google Earth Engine Timelapse website (it may load slowly, so give it a few moments) and navigate to a large scale view of your glacier. Press the pause button, then choose the 1984 view of the position of your glacier toe. Create a screen capture of this view and save it with the file name <5_Lastname 1984 imagery>. Add the image to your document as Figure 5 and write a caption indicating what the image is and use the “share current View” button to create a link and paste it as the image source (Figure 20.5).
Keeping the same view, repeat the steps using the 2018 imagery and save the screen capture with the file name <6_2018_Lastname_Glacier_extent>. Write a caption for Figure 6 describing any changes you observe (Figure 20.6).
8. Estimate the approximate location of the glacier toe in 1984 (creating a point feature and Figure 7).
Using the image of the 1984 imagery from the Google Earth Engine Timelapse website, add a point feature to your Google Earth project and move it to your best estimate of the location of the toe of the glacier in 1984. Use as many landmarks as possible to situate your point. Make sure your view is in 2D and it helps if you view both images ta the same scale.
Measure the length of the glacier you estimate in 1984 and create a screen capture of your measurement. Save this screen capture as <7_Lastname_1984_approximate_glacier_toe>.
9. Analyze the accumulation zone in the most recent satellite imagery (Figure 8).
Go to the USGS website tool for viewing recent satellite imagery (link below) and navigate to a large scale view of your glacier.
Find the date of the best Sentinel 2 MSI (2015-present) image capturing the minimum size of the accumulation area for the most recent year that there is 12 months of data. This generally occurs in late summer, so you will want to set the “Days of the Year” from early August to late September. For instance, if you are doing this lab in Fall 2025, you will need to use the 2024 images. See the video below on how to do this.
Once the images are loaded (this might take some time), ensure that you turn the “Dynamic Image Refresh” off. Press the play button (black triangle) until you find the best scene depicting the minimum size of the accumulation zone. Stop the video at this image. Record the image’s date (written directly below where it says “Active Date” in bold letters; e.g. August 27th, 2024).
Using the “measure tool” and then “location” button (circle with a cross over it) record the geographic grid coordinates in decimal degrees of the glacier toe. Once you have clicked the location, the coordinate appears in a table beside the green placemark icon.
Record the position.
Create a screen capture of the glacier and save it in a file named 8_Lastname_daymonthyear_Sentinel_2_image.
Add this file to your document as Figure 8 (Figure 20.8) and indicate the image source by adding the URL of your current view. Do this by using the “bookmarks” button then “Generate URL” button
Write a caption in which you describe and discuss the following questions:
a. What is the likelihood of the glacier disappearing in the current climate regime?
b. What observations are you basing your hypothesis on?
10. Calculate the rate of change (Figure 9).
Using the coordinates recorded in the previous step, add a point to your Google Earth project called <Year approximate glacier toe position>. E.g., “2024 approximate glacier toe position”
Measure the distance between this location and the 1984 position and calculate the average rate of retreat or advance of the glacier. Take a screen capture of this measurement and save the measurement as <9_Lastname_glacier_position_measurement>. Add this image to your document as Figure 9 (Figure 20.9).
Write a caption that includes the total measured retreat (or advance) distance over the period of 1984 until the most recent satellite imagery, and the rate of retreat.
11. Optional extra activity
If you are very ambitious and your goal is an A+ (or a great reference from your lab instructor), you may wish to do any of the following and add figures (screen captures) that support your data:
- Measure the area of the accumulation zone and express it as a percentage of the total area of the glacier in the image you captured in late summer.
- Find the oldest image of the glacier on the LandLook site (look for landsat images) and compare glacier length, accumulation zone area, and/or glacier area.
- Find imagery on the Atlas of Canada Toporama website or the Imap BC website and compare glacier toe positions.
12. Create a PDF file that you can submit for marks.
Review your text for grammatical and spelling mistakes.
Your lab instructor will likely require that you submit this assignment as a PDF that is a reasonable size (generally less than 5MB, but ask your lab instructor for details). You will need to reduce (compress) the file size of all of your images to between 150-96 ppi. This is done with
MSWord – > Picture Tools – > compress
Use to project that you titled <Lastname Firstname Glacier Survival Lab> to build your presentation. The presentation is built using the images and captions you wrote for your PDF document. When you have pressed the edit button feature for any of your point or line features, you can use the <Capture this View> button to make your presentation as attractive and instructional as possible. Below is a list the order of the features within your presentation. You can copy all your captions as the text for each feature. Title and organize the order of your features as described in the table below:
|1||Fullscreen slide||Your choice, but must include the glacier’s name if it has one.||The first line should include your name, the rest of your text can be your caption for Figure 1.||Figure 1|
|2||Full screen slide||Glacier topography||Caption Figure 2||Figure 2|
|3||Line||Glacier length||Caption Figure 3||Figure 3|
|4||Line||Little Ice Age||Caption Figure 4||Figure 4|
|5||Full screen slide||1984 glacier extent||Caption Figure 5||Figure 5|
|6||Full screen Slide||2018 glacier extent||Caption Figure 6||Figure 6|
|7||Point||1984 approximate glacier toe position||Caption Figure 7||Figure 7|
|8||Full Screen Slide||Sentinel-2 late summer image||Caption Figure 8||Figure 8|
|9||Point||2019 approximate glacier toe position||Caption Figure 9||Figure 9|
|Additional slides if you chose|
|10||Full Screen Slide||END|
- Figure 20.1 Huscroft 3D GE image © Google is licensed under a All Rights Reserved license
- Figure 20.2 Huscroft topographic map
- Figure 20.3 Huscroft glacier length © Google is licensed under a All Rights Reserved license
- Figure 20.4 Huscroft LIA extent © Google is licensed under a All Rights Reserved license
- Figure 20.5 Huscroft 1984 imagery © Google is licensed under a All Rights Reserved license
- Figure 20.6 Huscroft 2018 imagery © Google is licensed under a All Rights Reserved license
- Figure 20.7 1984 Glacier toe position © Google is licensed under a All Rights Reserved license
- Figure 20.8 Huscroft 29082019 Sentinel 2 image © U.S. Geological Survey is licensed under a Public Domain license
- Figure 20.9 Huscroft 2019 glacier toe position © Google is licensed under a All Rights Reserved license