Lab 2 Handout (1)
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University of Wisconsin, Madison *
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461
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Geography
Date
Feb 20, 2024
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2
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Lab 2: Environmental Systems, Glaciers When will the Glaciers disappear in Glacier National Park? Introduction: In this investigation, you will estimate how long it will be before there are no longer glaciers in Glacier National Park based on historical records. You will use three methods to estimate, visual estimate, hand mapping from historical images, and an excel file with measured historical data. You will predict when the glaciers disappear completely and then assess the two methods you used. This investigation is intended to build your skills and experience analyzing and interpreting real data for an environmental system. These historical records are summarized on a map of Grinnell Glacier, on the eastern side of the Garden Wall in Glacier National Park. (The map is from U. S. Geological Survey Professional Paper 1180: Grinnell and Sperry Glaciers, Glacier National Park, Montana: a Record of Vanishing Ice, published by the USGS in 1980. This paper is only one of many scientific studies of glaciers in the park, dating back to the early 1900’s). Grinnell Glacier is one of the largest remaining glaciers in the park, even though it is less than a square mile in area. More information about glaciers in Glacier National Park can be found here: https://www.usgs.gov/centers/norock/science/status-glaciers-glacier-national-park You will work in teams which your TA will assign. Each person will submit their own lab report with the following four sections. Please be concise with your writing and try to keep the lab report to two pages. Part I: Discuss in your group: 1.
Scientists have been studying the glaciers at Glacier National Park for quite some time. Why do you suppose they have done so? List at least two realistic reasons. 2.
The rate of recession for a glacier is best indicated by ice volume not area. List at least one reasons why you think that may be so. 3.
What else could we measure, that could be related to glacier volume? List at least three things. Part II: Make an initial prediction. Before analyzing any data, look at the images of Grinnell Glacier located at this link. https://www.usgs.gov/centers/norock/science/grinnell-glacier-mount-gould-1938-1981-1998-2015?qt- science_center_objects=1#qt-science_center_objects 4.
Based on only this evidence, approximately what year do you think the Grinnell Glacier is completely melted? (this is an educated guess, does not require any support data). Part III: Estimating based on images. Using the photocopies of the USGS map, outline the extent of Grinnell Glacier for four different years (1850, 1937, 1968, and 1993). Trace it onto the graph paper provided. Then count the number of squares of graph paper contained within your traced outline. Try to estimate by half or quarter squares for those that are partial squares. The total should be very close to the surface area of Grinnell Glacier that year, in “squares.” But how big is each square of your graph paper? Compare the squares of the graph paper to the map scale (one inch is 0.5km on the image). Convert your measured area to a more practical unit of measurement. Make a table of the years and the area you measured for each of the four years. 5.
Estimate what year you think the glacier will melt based on this data.
Part IV: Estimating based on data. In Canvas there is an excel sheet for Lab 2. Open the excel sheet. Complete the following questions by filling the equations needed in the excel sheet in the orange boxes. 6.
Of the 150 glaciers in the park in 1850, what percentage remained in 2009? •
Hint: percent remaining is calculated by dividing the final number by the initial number 7.
What is the % decrease in the number of glaciers from 1850 to 1966 and from 1850 to 2009? •
Hint: use the same equation above, but the numerator should include a subtraction to reflect the years you are interested in 8.
Using data provided (m
2
), what is the area (km
2
, miles
2
, ft
2
) of Grinnell Glacier each year given? •
Hint: convert units 9.
What is the estimated area (km
2
) of Grinnell Glacier for 1900? •
Hint: interpolate using the equation on the graph solve for y 10.
Using extrapolation, in what year will ice at what is now Grinnell Glacier be gone (0.0 km
2
)? •
Hint: use the quadratic formula to solve for x 11.
Using extrapolation, in what year will ice at what is now Grinnell Glacier be less that the area required to be classified as a glacier (0.1 km
2
)? •
Hint: use the quadratic formula to solve for x For questions 10 and 11 above you will need to remember the below formula. Part V: Interpretation. You have estimated the glacier melt by three methods. 12.
What are the three years that you came up with in the previous sections? What method do you think is most accurate and why? Extrapolating data into the future has some issues, what might those issues be in this example of a glacier melting? 13.
Lastly you should formulate a hypothesis, relating the rate of glacial retreat to some other variable. Dig up data on that other variable. Finally, see whether there is, in fact, a correlation between the rate of glacial retreat in Glacier National Park and the variable you have selected by plotting the variable you have selected with the glacier size in the excel chart. Whether there is a visible relationship or not, report your findings. PLEASE SUBMIT YOUR MAX 2 PAGE LAB REPORT AND YOUR EXCEL SHEET IN CANVAS. Please organize your report answers using the numbers within the lab handout.
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