Teaching Notes

Grade Level

This activity can be used for middle and high school students.

Learning Goals

After completing this unit, users will be able to:

  • Search for, request, and download climate data for the Lake Champlain region
  • Manipulate data in a spreadsheet to produce graphs
  • Compare multiple sets of time series data, including with linear regression models
  • Analyze graphs to interpret trends in temperature and its effect on ice formation
  • Analyze the effects of future climate change on the region using predictive global climate models

Rationale

Lake Champlain is a major source of tourism, recreation, and ecosystem services for residents of New York, Vermont, and Quebec, Canada. The lake provides services to residents and tourists year-round, with boating, fishing, and swimming during the summer, and ice fishing and ice skating during the winter. Ice fishing shacks are commonly seen on the lake during the winter season; however, it has been observed that the lake has not been freezing as completely in the last several years. Should this trend continue, some of the services the lake provides to residents and tourists during the winter may become unavailable or unusable.

In this unit, students will explore the variations in surface air temperature in the Lake Champlain basin, determine the extent to which the lake freezes currently, link air temperature changes with changes in ice formation, and predict how ice formation on the lake will be impacted by climate change trends in the future.

Key Concepts and Vocabulary

Lake Closing: A lake is considered “closed” when it is fully covered by ice. A lake closing date is the date at which the lake becomes fully covered with ice, and a year when the lake did not close means that ice did not fully cover the surface of the lake (some open water remained exposed).

Julian Date: The number of days between a given date and January 1st, for example the Julian date of February 1st is 32.

Background Information

Lake Champlain is a freshwater lake located over an area that encompasses Vermont, New York, and the Canadian Province of Quebec. This lake provides drinking water to approximately 200,000 people and attracts $3.8 billion in tourism every year. It is also the home to over 81 fish species, 300 bird species, and 541,00 people.1,2

Water quality and management of invasive species are problems currently being monitored in the Lake Champlain Basin. With the effects of climate change currently occurring, more problems will arise. Changes in precipitation and temperature throughout the upcoming years will force humans and other species in the area to adapt.

Two changes that have been observed over the last several decades are the dates that the lake “closes,” or freezes over, and the number of years when it does not close at all (never freezes completely). Stager et al.3 report that earlier ice-out dates (date when the last remaining ice leaves the lake) are commonly reported in the region, but the dates of lake freeze-up in the Champlain Basin vicinity are changing much more rapidly. For example, freeze-up at Mirror Lake in Lake Placid, NY now comes 12 days later than it did a century ago, but spring ice-out is only two days earlier. Lake Champlain freezes roughly two weeks later than it did during the early 1800s and about nine days later on average than in 1900. In the thirty seven year period between 1970 and 2007, it did not freeze completely nearly 50% of the years. Ice cover on lakes is important in terms of controlling water temperature and, therefore, it ultimately affects the lake’s suitability as a habitat for native species. Ice and snow cover reflects solar heat, keeping it from entering a lake.3

The two primary resources for understanding Lake Champlain and the extent of the expected changes are the Lake Champlain Basin Program, which is administered by several U.S. and Canadian federal and state/province agencies, and the Nature Conservancy.

      1. Students will access and review weather station data for Burlington VT.  There are two options:
      1. The U.S. federal agencies NASA and NOAA (National Oceanic and Atmospheric Administration) use satellites to “take pictures” of the earth to help understand weather and climate. The MODIS instruments aboard the Terra and Aqua satellites were used to visualize Lake Champlain ice and are made available on NOAA’s web site for Burlington VT some of the recent images are compiled in an Adobe pdf file for easier access. Students will review these images and answer several questions.
      1. The dates that ice coverage on Lake Champlain has closed are provided by NOAA.  These data have been compiled into a spreadsheet for your use. Using these data, students will answer several questions.
      1. The Northeast Climate data site (www.northeastclimatedata.org) provides predictions for high and low carbon dioxide emissions (a tutorial is available to guide the student through this web site). Students will use the Northeast Climate Data site to explore predicted changes in temperature and to infer changes in ice coverage. The models include several potential scenarios for the future.  The students will examine the worst case high greenhouse gas emission scenario (A1) and the lower emissions scenario (B1) to evaluate the range of predictions for our future climate and answer several questions.
      • ·       Northeast Climate Data
        • Historical and predicted values for temperature and many climate indicators
        • Results of Northeast regional climate change models for A1 (worst case) and B1 (GHG mitigation) scenarios available for download into ASCII files (and summarized in the attached MS Excel workbook)
        • ·       Lake Champlain Climate Wizard
          • o   A graphical representation of climate change focused on the Lake Champlain basin, with temperature units available in Fahrenheit
      • Data from the United States Historical Climate Network (USHCN) Burlington, Vermont weather station which has already been compiled into an MS Excel spreadsheet
      • Alternatively, the students can access these data readily from the NASA GISS web tool that provides a easy graphical interface and data download capabilities. A tutorial is available to help students navigate this tool. The students should download the dataset and save it as an Excel file.  They will need to use the winter seasonal average temperatures or the monthly data for the winter months.
    • Present and Historical Data

      Predictive Tools and Data

      Instructional Strategies

      General Approach

      This module uses monthly average temperatures at a weather station in Burlington, Vermont, and historical dates of lake closing. The students review temperature data to see how the climate has changed over the 20th century, especially during winter months that are critical to ice formation on the lake. The students also review the dates that the lake closed in winters past, or if the lake closed at all, and correlate the frequency of lake non-closings with winter temperature data. Depending on students’ quantitative skills, they can be expected to use some basic MS Excel functions and create graphs to illustrate changes.

      It may be advantageous to have students work in small groups; students less familiar with the software could be teamed with more experienced computer users.

      Implementation

      Anticipatory Set Students should have some familiarity with general concept of climate change before beginning.  This module will help students understand the abstract notion that a change of a few degrees of temperature can have an impact on ecological systems.  Discussions of lakes, winter recreation on lakes and any familiarity with Lake Champlain in particular can help to provide some context for the unit.  Having students ask any older people they know, who enjoy outdoor winter recreation, what they have noticed about ice formation and duration changes over their lifetimes could provide additional anecdotal evidence of the consequences of climate change.  A student worksheet is available to guide the students through this project.

      Procedure

      The data can be graphed to evaluate historical changes in temperature from 1900 to the present. The students will then review the data present and generate graphs to answer several questions.

      Students should submit their work in the student worksheet included with this module.

      Closure Review the student findings and discuss the limitations in this type of analysis.  Identify other climate changes that they can expect to occur (e.g., other winter sports affected in the New York area) and what we might do t adapt to these changes. Discuss how their results might affect their attitudes towards the reality and consequences of climate change.

      Learning Contexts

      This module is particularly appropriate for an earth science class, especially in conjunction with a unit on weather or water bodies.  The data manipulation and generation of bar graphs or scatter plots with linear regression models are good extensions to math classes.

      Science Standards

      National Core Science Standards will be added when finalized.

      Assessment

      A standard laboratory report rubric can be used to assess the student reports.

      Other Resources

      Lake Champlain Data File – Lake_Champlain_Data_File.xlsx

      Student Worksheet

      Tutorial – Excel basics

      Tutorial – NASA GISS Surface temperature analysis web-based data access tool

      Tutorial – Using the Northeast Climate Data Website to access model prediction of our future climate

      Satellite images of Lake Champlain ice, winter 2011

Step-By-Step

Part 1: How has the temperature in the Lake Champlain region changed over the last century?

Part 2: How much ice forms on Lake Champlain?

Part 3: How has ice formation on Lake Champlain changed over the last several decades?

Part 4: How will temperatures and ice formation change over the next century?

Part 1: How has the temperature in the Lake Champlain region changed over the last century?

Winter (December, January, and February) air temperature data are summarized in the MS Excel spreadsheet (Lake_Champlain_Data_File.xlsx). Data are available for each year from 1896 to 2008. These data have been processed somewhat to make the module suitable for the targeted grade; however more advanced students can be asked to retrieve and process the data themselves from the NASA GISS surface temperature analysis web tool.

  1. Access data:
    1. For use of the existing Excel spreadsheet: Open the MS Excel spreadsheet, click on the “Burlington Winter Temperature” tab at the bottom of the workbook.
    2. For downloading data: Follow the steps in the NASA GISS tutorial to access weather station data.  Find the data set for Burlington VT and complete all steps for accessing monthly data and opening these data in MS Excel.
  2. Annual temperature trends: Create a graph to illustrate the how annual winter temperature has changed over time. Fit a linear equation to the data (see the Excel tutorial if additional Excel help is required).  Include the equation for your trendline on your graph.
  3. Decadal temperature trends:
    1. Using the annual winter temperature data, find the average winter temperature in each decade from 1900-current.
    2. Create a graph to illustrate how decadal average winter temperature has changed over time. Fit a linear equation to the data. Include the equation for your trendline on your graph.
  4. Answer the following discussion questions:
    1. Has the annual average or winter temperature in Burlington Vermont changed very much over this time period? 
    2. What trends do you see in increasing or decreasing temperature?
    3. Does observing the average the winter temperatures over each decade (1900-1909, 1910-1919, etc.) help you evaluate long term changes in temperature?

 

Part 2: How much ice forms on Lake Champlain?

The following section uses MODIS satellite pictures of the lake, which are available for viewing and download at http://www.erh.noaa.gov/btv/html/lake.php. You will need to scroll down to the paragraph labeled “Lake Champlain Ice Coverage (MODIS Satellite Imagery)”, toward the bottom of the page. It may be helpful to download these images and arrange them chronologically beforehand to facilitate viewing in class. A sample set of images from December 2010 to April 2011 is available in Champlain_Ice_Cover_2011.pdf.

  1. Review the images available.
  2. Discussion questions:
    1. How does the ice coverage change over the course of the winter?
    2. Of the pictures available, what were the approximate dates that you can see ice coverage beginning and ending?
    3. Did the Lake freeze completely?  If not, what are the characteristics of the areas of the lake that did or did not freeze?
    4. When did Lake Champlain fully melt?

Part 3: How has ice formation on Lake Champlain changed over the last several   decades?

The dates that ice coverage on Lake Champlain has closed are provided by NOAA (http://www.erh.noaa.gov/btv/climo/lakeclose.shtml ), and have been compiled into the MS Excel spreadsheet.

  1. Open the MS Excel spreadsheet – “Closing Dates” spreadsheet page.
  2. Review the annual closing date of the lake.
  3. Question:
    1. Do you notice any trends in the number of times the lake is “Not Closed”?
    2. Count the number of times the lake did not close in each decade between 1900 and 2010 (denoted as “n/a” under Julian Closing Date). Plot a column graph of number of times the lake did not close with respect to decade. Fit a linear equation to the data.
    3. Questions:
      1. How many times has the lake not closed, over every decade for the time period shown?
      2. Are there any trends in the frequency of non-closing years over time?
    4. Review the data for the years where the lake did close (not including “n/a” entries). Plot the Julian closing date as a function of the year. Fit a linear equation to the data.
    5. Questions:
      1. Are there any trends in these dates over time?
    6. Create a graph to examine the relationship between lake closing and temperature.  Plot “Number of ‘Not Closed’ Per Decade” as a function of “Decadal Average Winter Temperature” (from the “Burlington Winter Temperature” sheet). Fit a linear equation to the data.
      1. Is there a relationship between the number of non-closings per decade and winter temperature?
      2. Make an hypothesis about the relationship between winter temperature and number of non-closing occurrences.

Part 4: How will temperatures and ice formation change over the next century?

Scientists predict that the temperature in New York State will continue to rise throughout the 21st century.  The predictions of the possible temperature rise depend on the expectations of how our populations will grow and what technologies are developed over this time period.  Mathematical models of our climate were used to predict temperature in New York State.  The results are available through the Northeast Climate Data Center.  Predictions are provided for two cases.  The A1 scenario is the worst case and B1 a less severe case, with expectations that we take a global and environmentally oriented approach to development over the next century.  Use the tutorial for the Northeast Climate Data Center web site to find maps of predicted winter monthly or seasonal temperatures for the end of the 21st century.

  1. Discussion questions:
    1. What are the average future winter temperatures expected to be? 
    2. What increases in winter temperatures for Lake Champlain region does each scenario predict relative to the current temperature?
    3. Plug the winter temperature predictions into the equation derived in Part 3, Step 8, where “x” is equal to the predicted winter temperature. Note: If the equation output is greater than 10, the lake is not predicted to close at all that decade, and if the equation output is negative, the lake is expected to close each year.
    4. Discussion questions:
      1. What do you expect will happen to the number of years in each decade that Lake Champlain will not close?
      2. How will these changes in ice coverage over the next century affect the Lake as an ecosystem? How might they affect people, habitat and society?
      3. What are the potential errors in your approach and analysis?  Discuss the values and limitations of your work.

Tools and Data

Tools

Microsoft Excel: A spreadsheet application is needed to analyze the data. Microsoft Excel is used in this chapter and is available as part of Microsoft Office.

Tool Builder

Microsoft Corporation - www.microsoft.com

Tool Cost

Excel is part of the suite of Microsoft Office software. Students and educators may be able to purchase this software at a reduced cost. The Student and Home Edition is sufficient for use in the Earth Exploration Toolbook chapters.  Open office, a free software can also be used.

Data Sets

Data Set 1

Burlington Vermont Monthly Average Surface Air Temperature

Data are provided by the United States Historical Climate Network (USHCN) from the “Burlington WSO AP, VT (431081)”weather station. Data were then processed to show seasonal average surface air temperature and are as shown in the MS Excel spreadsheet, “Burlington Winter Temperature” page.

Data Provider

USHCN http://cdiac.ornl.gov/epubs/ndp/ushcn/ushcn.html

These same data are also available through the NASA GISS Surface Temperature Analysis web tool

Data Set 2

Lake Champlain Closing Dates

The data are a list of years and the date the lake closed. If the lake did not close during a particular year, the data point is marked “not closed”. These data were copied from the National Oceanic and Atmospheric Administration (NOAA) website into the MS Excel file and processed to show Julian date, and the number of “not closed” data points per decade.

Data Provider

NOAA National Weather Service Forecast Office, Burlington VT

http://www.erh.noaa.gov/btv/climo/lakeclose.shtml

Data Set 3

Northeast Climate Data Predictive Models

Data are New York State average winter temperature for two scenarios predicted annually to 2099. Data presented in the MS Excel spreadsheet, “Climate Models” page, are “time series” data, and can be used to predict temperature in any given year.

Data Provider

Northeast Climate Data www.northeastclimatedata.org/