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INTRODUCTION: Scientists tell us that glaciers in the polar regions are shrinking, but how do they know this? What might be causing this change? You will examine measurements from Antarctica’s Pine Island Glacier (PIG) to see if change can be detected over a four year period, and then develop a physical model to explain what is happening to PIG, and how this connects to climate.

Image 1) Glaciers are large expanses of ice, often covering the landscape - images 1 & 3 - Greenland’s Kangerdlugssuaq Glacier (by P. Spector)

Image 2) Arrow points to the calving front on Greenland’s Jacobshavn Glacier (by I. Das)

REVIEW OF GLACIER BASICS: Glaciers are rivers of ice but how do they develop? Forming a glacier: In some areas snow lasts on the ground all year. Newly falling snowflakes cover the older snowflakes, compressing them to be smaller and denser. Air between snowflakes is pressed out, and over time as the snow deepens it crystallizes into ice. Ice Sheets: Ice sheets are continental size glaciers. They exist today in Greenland and Antarctica. Glacier Growth: Glaciers grow when annually more snow is ADDED (accumulation) than is REMOVED (ablation). Snow can be added directly through snowfall, or blown in from other areas by the wind. Glacier Movement: As glaciers grow from snow accumulation they stack higher and higher causing gravity to tug, pulling them down. Glaciers are called ‘rivers of ice’ since they move constantly flowing from areas of higher elevation to areas of lower elevation.

Glacier Change: As a glacier flows to lower elevations it can lose mass (ablation) several ways: melting - lower elevations are generally warmer; wind - wind blowing over the glacier erodes the surface; sublimation - ice can turn directly to vapor without moving through the liquid stage; calving - chunks of ice that break off at the glacier edges. Glacier Retreat: Remember as glaciers flow to lower elevations they lose mass. Glaciers will retreat when there is less new snow accumulation than ablation (Image 4).

TASK: Where would you expect accumulation and ablation to occur on a glacier? Label the glacier in Image 3 with these words to show your choice.

POLAR I.C.E. (Interactive Climate Education)

WHAT IS HAPPENING TO ANTARCTIC’S PINE ISLAND GLACIER? Use your understanding of glacier science to figure out what is happening to this Glacier!

Image 3) Kangerdlugssuaq Glacier

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Image 4) A Glacial System (edited from R. Bell, The Unquiet Ice, Scientific American, 2/08)

Basic Glacier Equations – it is simple math!

Balanced/Steady State Glacier: Annual new snow =Annual snow melt/loss Glacier Expansion/Growing: Annual new snow > Annual snow melt/loss Glacier Retreat/Shrinking: Annual new snow < Annual snow melt/loss

MEASURING POLAR ICE: Scientists are measuring the polar ice sheets to determine both how fast and how much (total amount) they have changed over the last few years but it isn’t easy! Why? The polar regions are large, the weather is extreme and there are few roads for travel. Much of the ice is not smooth, and huge deep breaks in the ice, called crevasses, can appear suddenly in the snow adding to the travel difficulties! One of the most efficient ways scientists have found to collect measurements is from above the Earth’s surface using satellites and aircraft. These types of measurements are called ‘remote sensing’, which simply means the instruments are not physically touching the objects they are measuring. A lot of our understanding of the Earth has come from remote sensing.

Since the 1990s satellites have been collecting information on the Earth surfaces. In 2003 NASA launched a satellite specifically to collect ice measurements in the polar-regions (Image 4). “Ice, Cloud and Land Elevation Satellite” (ICESat) collected ice sheet surface elevation (height) as one of its measurements since a glacier that is dropping in elevation is losing ice. You will be working with ICESat data to determine if the ice surface is changing. ICESat used a laser to measure ice surface elevation. Light travels at a constant speed so lasers

send a light beam to the ice surface and the travel time is measured and then converted to distance.

5) NASA ICESat used a laser to measure the ice surface elevation. It’s measurements are accurate to ~15 cm (6 inches) of elevation!

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MEET PINE ISLAND GLACIER (PIG) - ONE OF ANTARCTICA’S FASTEST CHANGING GLACIER!

6) Antarctic Glacier Velocity Map (original by NASA) – Annotated to highlight PIG’s location in the boxed area. The arrow shows ice flow direction.

When ICESat was launched scientists were already interested in Pine Island Glacier (PIG), a ‘stream’ of fast moving ice. Examine the Antarctic map in Image 6 and locate the box outlining PIG. Considered the largest of 3 major pathways draining ice from the West Antarctic Ice Sheet, PIG flows directly into the Amundsen Sea. Image 6 shows ice speed or velocity (note the key). Satellite measurements show that PIG is accelerating, moving ice at speeds measured at 3.5 km/yr, and pushing more ice into the ocean than any other glacier in Antarctica! As the more ice moves into the ocean the ice surface will loose elevation.

Image 7) Map of the largest of Antarctica’s Ice Shelves. The shelves in this image are colored and labeled with ice volume – by T. Scambos, National Snow and Ice Data Center Much of Antarctica is surrounded by large ice shelves, which isolate the glaciers from the warming ocean, and work like a ‘dam’ holding the ice on the land. Think of the ice shelves as gates at a horse race and the glaciers and their ice streams as the horses. Once the gates, or ice shelves, are

removed, what is behind them accelerates! But how are the ice shelves removed? There is evidence that warming ocean water is being forced up around the edges of Antarctica by

East

Antarctica

West

Antarctica

Amundsen Sea

Pine Island Glacier

Pine Island Glacier

ANTARCTICA

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shifting ocean currents, causing melting and weakening where the ocean touches the ends of the ice shelves. Melting the edges of the ice shelves causes them to break apart, opening the ‘gate’ holding back the ice, causing ice flow to accelerate and ice surface elevation to drop. Look closely at Image 7. There is no large ice shelf protecting PIG. PIG’s ice shelf is so small it is barely visible so it is not colored or labeled. PIG’s ice shelf measures ~ 40 X 20 kms in size. Task: Calculate the area of PIG’s ice shelf _______. Compare its size to the other ice shelves in Image 7. ________________________________________________________________ How do you think the size of the PIG ice shelf might relate to the speed of its glacier? Answer and Explain: _________________________________________________________________________

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PART 1: WORKING WITH ICESat DATA Activity: Are changes occurring in the elevation (height) of PIG? Scientists have been reviewing satellite data on the surface elevation (height) of the PIG glacier over several years to see if there is a loss of ice. Remember, if the height of the glacier drops it shows a loss of ice and a shrinking glacier. If the height increases it means the glacier is growing larger. Help the scientists determine what is happening!

Image 8 shows a close up of a satellite image of PIG. The arrow runs along the ice stream in the center of PIG. Ice streams are the fast moving center of the glacier that acts like a conveyor belt as it moves ice. (You can look back at Image 4 to see how an ice stream fits into the ‘glacier system’.) The red line on the top shows where the data from this activity was collected. The data: You are working with real data collected over PIG survey line # 279 on three separate times:

Image 8) A Satellite image of Pine Island Glacier Flow. The top line shows where the data was collected for this activity. The arrow matches the location arrow on image 6.

Nov. 2003, April 2007 and Oct. 2007. We will examine these three sets of data to see if there are changes occurring in the glacier over this four year time period

What was measured: The data you will work with was collected along a line across the front of PIG the same way that the line on Image 8 cuts across the glacier front. The data measures the elevation (height) across the glacier front at multiple points. Collected in this way along a line, the series of data points represents a ‘slice across the glacier’. Data was collected in the same location repeatedly in different months and years in order to assess any changes. PIG 279 – Part I

1. The full PIG #279 dataset contains hundreds of data points. A small representative section of the data is provided here for you to analyze.

GRAPHING PIG DATA FOR LINE #279

LOCATION KM

METERS/ ELEVATION

11/2003

METERS/ ELEVATION

4/2007

METERS/ ELEVATION

10/2007 239 777 778 778 240 711 712 711 241 443 439 439 242 347 340 339 244 235 218 216 246 325 309 306 248 477 465 469 250 557 545 545 252 557 553 553 253 690 687 687

2. Let’s start by looking at what each of the four columns represents.

Glacier flow direction

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• Location km - Shows the location of each data point as a km from a central

starting point. Since we are looking at only a section of the data we have only data points between km 239 through km 253. What is the total distance represented by the data points in this graph?________

• Elevation & Dates of Measurements – There are three columns of elevation

data for PIG 279, labeled by month and year 11/2003, 4/2007 and 10/2007. Each of these is called a ‘data series’ as it represents the ice elevation at the same set of locations for the three time periods. The elevation measurements are listed as the depth of the ice in meters.

3. What is the first step in analysis? When scientists collect more than one ‘data series’

they look at them together by plotting or graphing them to see if there is a relationship. Plots and graphs can help us to ‘see’ the data to recognize patterns and trends. For this data we have the locations by km and the elevation by date so let’s plot it on a graph.

4. You can use the Graph Paper labeled Graph #1 to create a graph that includes all three

sets of data from the first 4 columns on your sheet, or you can use the attached excel file .xls or .xlsx to work with the data. First set up the ‘X’ and ‘Y’ axes. The ‘X’ axis will be the distance in km. Decide how you will set up your ‘X’ axis with numbers ranging from 239 to 253. For your ‘Y’ axis, locate the highest_____ and lowest____ elevations over the three years and set up your axis to cover the range you need.

5. You are ready to start plotting the official ICESAT ice elevation data! Select a different

color pencil to plot each of the three sets of data so that they will be easily recognized as a separate line with its own label and color. Be sure to make a color key on the graph. Starting with ‘Elevation 11/2003’ plot each of the three sets of data, connecting the data points within each year with a line.

6. Examine your chart. Can you tell if there is a story in the data displayed? Do you see

elevation changes or does it appear that the ice surface has been fairly stable? Describe what you see. ________________________________________________________________________________________________________________________________________________

7. Let’s look a little closer. The data collected is from a length of approximately ___ kms,

with altitude changes of almost ____ meters. This is a fairly large area to examine for what could be changes of only a meter or so. We need to figure out a better way to look at the data given this scale. Let’s try something new!

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PIG 279 – Part II

GRAPHING PIG DATA FOR LINE #279 LOCATION

KM METERS/

ELEVATION 11/2003

METERS/ ELEVATION

4/2007

METERS/ ELEVATION

10/2007

DELTA 11/03 to APR 07

DELTA 11/03 to OCT 07

239 777 778 778 1 1 240 711 712 711 0 241 443 439 439 -4 242 347 340 339 -7 244 235 218 216 -17 -19 246 325 309 306 -16 248 477 465 469 -8 250 557 545 545 -12 252 557 553 553 -4 -4 253 690 687 687 -3

8. What if we use Nov. 2003 as our base level and compare the two 2007 data sets

against it? This will show us how PIG’s elevation has changed over time but using the difference from 2003 the numbers will be much smaller and it will be easier to see if there has been a change over the four years of data collected. Let’s look at the 2 new columns added to the chart to see what each one represents.

• Delta means change. These last two columns represent the elevation change from the 2003 for each of the 2007 measurements. For example at km 239 the April 07 reading of 778 is 1 above the Nov. 2003 reading of 777 so the amount listed is 1. If the 2007 number is below 2003 it will be a negative number. The first row is complete for you. Fill in the missing numbers for the rest of the graph. Pay attention to negative versus positive numbers.

9. Before we start to chart the data think about what the numbers will mean. What would a

positive ‘delta’ number mean? What would a negative Delta number mean? In other words, which would mean LESS ice and the glacier is shrinking___________, and which would mean MORE ice and the glacier is growing? _______________

10. Chart the data on the sheet marked Graph #2 or use the attached excel file. Use the

change from 2003, or the delta number for each year. The numbers you put for the ‘X’ axis will be the same as the last graph since the distances have not changed. The ‘Y’ axis will still be called “Elevation” but this time the ‘Y’ axis will be the difference from the elevation measured in 2003 for the 2007 ICESat data. What is the highest_____ and lowest____ elevation listed for the three years? Now set up your axis to cover the range you need. Use the same key and colors as you did for graph in Part I and remember each set of data will be a separate line with its own label and color.

11. Now that it is graphed let’s examine your chart. Can you find a story in the data

displayed? Do the data points overlap, or are there clear differences? Discuss a comparison of the data from November 03 to the data from April 2007 and then to Oct. 2007? Be sure to use dates and measurements in your answer. ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

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12. Just how much change is this? Look back at the data and recall the unit of measure used.

____________ Looking at the changes you recorded in your last two columns consider how this compares to the amount of snowfall in the winter in your state. Do you feel this is a significant change in elevation? ________________________________________________________________________________________________________________________________________________

13. What does this data tell us about the PIG glacier? Think back to what was discussed

as causes for changing elevation in glaciers. List at least one thing you think could be contributing to change in this area of Antarctica? ________________________________________________________________________________________________________________________________________________

14. We have looked at one series of PIG data, however scientists would want to look at

more than one data set. Why would this be important? ______________________________________________________________________

______________________________________________________________________

15. Line 362 is posted as a separate excel file. This is a second set of PIG data that you can work with if you would like to do a further comparison.

Develop a model. What causes the glacier elevation to behave this way? In Part III you will complete a lab creating your own hypothesis about glacier movement and experimenting with it. Following the scientific method you will experiment with glacier behavior using a physical model:

1. Construct a hypothesis 2. Test it by doing an experiment 3. Analyze your data 4. Draw a conclusion 5. Communicate your results

A Few Additional Resources: Short background video on NASA’s ICESat: http://icesat.gsfc.nasa.gov/icesat/photogallery/anim/package_no_titles.mpg R. Bell, 2008, The Unquiet Ice, Scientific American, p. 60-67.

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PART III: HANDS ON LAB ACTIVITY - WORK WITH GLACIER GOO TO DEVELOP A MODEL TO SUPPORT THE DATA (For this section students work in a team of 2-4. Give each student the work sheet)

Image 9) Supplies used in lab

SUPPLIES: Set up needed for each team: • Batch of Glacier Goo (recipe attached) • Small Rectangular container (we used

plastic box ~13" x 7-1/2" x 4-1/4" h) • Flat ‘ramp’ for container firm enough to

support glacier goo (wood, plastic, etc.) • Marked graph measuring paper (attached)

laminate or place in plastic sleeve • Dry erase marker • Tape • Plastic knife • Stop watch • Calculator • Ruler with centimeter measurements

LAB ACTIVITY: The set up can be done in advance by the teacher or by the students with teacher supervision. SET UP:

• Set up your rectangular container with a sturdy ramped surface for the glacier (goo) to flow on (the goo can be surprisingly heavy so less rigid surfaces will bend).

• Tape one copy of the laminated gridded graph paper to the ramp, underneath if it is clear or on top of the ramp if it is not (see Image #11)

• Make sure each team has the full list of supplies. Before You Start: You will be using glacier goo as a model for polar glaciers in this section. Before you start review the following questions answering in full sentences:

1. Thinking back to the ‘Glacier Basics’, are glaciers rigid blocks of ice? Explain. ________________________________________________________________________________________________________________________________________________

2. What is needed for a glacier to maintain a steady surface elevation (height)? Remember

the equation! _______________________________________________________________________

3. Could a change at the ablation zone of the glacier cause a change in the elevation of the

glacier? Explain. _______________________________________________________________________

4. Recall the data you graphed for PIG. State your hypothesis below to explain the changes

in the PIG glacier. ________________________________________________________________________________________________________________________________________________

Now you will use your model to test this hypothesis.

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ACTIVITY # 1: TEST YOUR HYPOTHESIS: Let’s collect some observations and measurements of our glaciers (goo).

Image 10) Mark the glacier surface height and 1 cm below the surface with lines. Mark the terminus (end) of the glacier with a line.

Image 11) Measuring the grid. The arrow is pointed to the pre-marked square on the grid.

MAKING OBSERVATIONS

1. What makes glaciers move in nature? ____________________ Mound your glacier (goo) on the top of the ramp. Release and describe your glacier (goo) movement: ________________________________ How is the glacier goo like a real glacier?______________________________________________________

2. Establishing The Base Level: Use ¾ of a batch of glacier (goo). Have one student

mound it on the ramp, holding it in place during set up. Arrange the glacier (goo) in the container so that any change in elevation will be visible through the side ‘wall’ of the container. Set the goo slightly away from the wall since the goo will stick to the ‘walls’ of the container. (Note: As the goo moves if it does stick to the wall carefully use your plastic knife to skim it off to see the glacier surface level.)

Have a second student place a piece of clear tape on the outside of the plastic container and using a dry erase marker put a mark at the surface height of the glacier. Use your ruler to make a parallel line 1 cm below this surface mark and label it 1 cm drop (see image #10). Now place a mark at the end point (this is called the ‘toe’) of the glacier. These lines mark your glacier ‘base level’. You will now be able to return to this base level with each ‘run’ of your experiment and be able to see what happens to this base level with changes you make in the conditions.

3. Elevation Run #1: Remove your hold on the glacier (goo). Time and observe for 2

minutes. Measure and describe any changes to the surface elevation. (Refer to your markings on the side of your container.) Does one of the glacier equations from Glacier Basics match this demonstration? _________________________________________________________________

4. Elevation Run #2: Start your glacier over again. This time as the glacier flows add ‘new

snow’ some of your remaining glacier (goo) to the top of the glacier ever 30 seconds. Compare run #2 to run #1? Does one of the glacier equations from Glacier Basics match this demonstration? __________________________________________________________________

5. Elevation Run #3. What if the ice at the base of the glacier were to melt from the ocean water warming it? Start your glacier over again, and let it run for 1 minute. Remove

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some of the ice at the toe of the glacier by cutting a section off with a plastic knife. Watch what happens. Does the glacier speed up or stay the same? ________ _____________ Does it losing elevation or stay the same? ___________________

6. Compare to Your Hypothesis. Does the behavior of this model glacier support your

hypothesis? Explain. _________________________________________________________________

7. What other data would be useful to further test your original or a new hypothesis?

____________________________________________________________________

ACTIVITY #2: COLLECTING MEASUREMENTS: 8. Elevation Change: Next let’s collect some measurements to see how your glacier

measures up to the PIG glacier. Using the stopwatch you are going to measure how long it takes the glacier to lose the 1 cm of elevation you have marked on the outside of your container. Place the glacier (goo) in a mound at the top of the ramp. Set up the goo so the glacier surface lines up with the markings you have noted on the ‘wall’ and the toe of the glacier is in line with the terminus mark. Release the goo and start your stopwatch. Stop the watch when the glacier has dropped to the 1 cm drop marked on the wall. (Report in seconds)

Repeat 2 other times and compute an average.

________________ ________________ ______________ ________________ Time 1 Time 2 Time 3 Average The average elevation change you calculated is:

1cm/_____secs

9. Velocity: Now you will look at the velocity (rate of flow). Using a stopwatch you are going to measure the velocity of your glacier & then compare it to the velocity of PIG. In its fastest flowing sections PIG has been measured at ~3.5 km/yr.

To start, use your ruler to measure the specially marked grid on graph paper attached to your ramp. This will be your distance (D). How many cm long is it?__________

Reposition the glacier at the top of the ramp. Place your glacier (goo) so that the ‘toe’ (end) of your glacier is above the grid you just measured (Image #10). Using your stopwatch you will time the glacier as it flows the length of the measured square on your grid. Start the stopwatch as soon as the tip of the glacier reaches the top of the marked square and stop timing as soon as it touches the bottom of the marked square. Record the time below. Repeat twice more to get an average time (report in seconds).

_______________ _________________ _________________ ___________ Time #1 Time #2 Time #3 Average Time

What is your Velocity? Velocity = Distance/Time (V = D/T) ______ = ________/________

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PART IV: COMPARE YOUR GLACIER MOVEMENT TO PIG: How does your glacier match up to PIG? You have measured the elevation change and velocity of your glacier - let’s see how your data matches PIG!

PIG GLACIER GOO

10. Compare your glacier elevation changes to PIG. How long did it take PIG to loose 1

cm in elevation? Use Nov. 2003 to October 2007 as the timeframe rounding the time to 4 years. You have several elevation measures for PIG, but looking at the last 2 columns in your chart find the row across that shows the largest drop in meters and write it in the blank below. _______ Start with: meters_____/years_____

To better compare the two sets of measures convert the (a) meters to cm

(a) #meters____ X 100 cm = ______cm/_____years AND then ____cm/1 yr

b) ____days per year is ___ cm/___days OR _____ cm /1 day How many days to drop 1 cm? PIG ___days/_1_cm Glacier Goo 1cm/____ secs. PIG 1 cms/______days Glacier Goo 1cm/____secs.

How does your glacier elevation change compare to PIG? _________________ ________________________________________________________________

11. Compare your glacier velocity to PIG’s velocity. You will need to do some conversions to be able to compare these velocities. Let’s convert the PIG velocities into your recording units. Velocity of PIG = 3.5 km/year Compared this to your glacier velocity V____=______cms /_____secs To do this conversion you will need to know how many (a) cm are in a km and how many (b) minutes are in a year. (a) Convert to meters. 1000 meters (m) in a kilometer (km) and100 centimeters (cm) in a meter. How many cm are in 3.5 kms? _________

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(b) Convert years to minutes. _____ in a year X # hours in a day X # minutes in an hour?________ The Velocity of PIG _______cms/ __________ mins Your glacier velocity _________cms/_________mins

How far each glacier moves in 1 minute? Divide the cms by the number of minutes: The Velocity of PIG _______cms/min Your glacier velocity _________cms/min

How does the velocity of your glacier relate to PIG?____________________________

12. Glacier goo is not the same as a real glacier but it can help us learn about real glaciers.

What are three things you have learned about PIG working with your own glacier model, at least one should mention a connection to climate. ________________________________________________________________________________________________________________________________________________________________________________________________________________________

Mix#1:

One 20 oz cup 1 stirring stick

3/4 cup warm water 1 cup Elmers white glue

Mix#2:

one 8 oz cup 1/2 cup warm water

one stirring stick (for the 8 oz cup) 2 tsp. Borax powder

1 qt plastic zip lock bag ************************************************************************Mix # 1: In the large cup, add 3/4 cup warm water and 1 cup glue. Stir until well mixed. Mix # 2: In the smaller cup, measure 1/2 cup warm water. Add 2 tsp. of Borax powder. Stir until the powder is dissolved. Pour Mix 2 (the powder mix) into the glue mix. Stir until a glob forms and most of the water is mixed in. This happens quickly! Knead and work the mix for 2 – 3 minutes. Most, if not all, of the water will be incorporated into the mixture. Place the glacier goo in the zip lock bag. The mixture will store for a few months.

POLAR I.C.E. (Interactive Climate Education)

GLACIER GOO

For Use in Modeling Glaciers

Free Plain Graph Paper from http://incompetech.com/graphpaper/plain/

Free Plain Graph Paper from http://incompetech.com/graphpaper/plain/