EarthLabs > Earth System Science > Lab 3: Discovering Local Data > 3B: Graphing GLOBE Data

Lab 3: Discovering Local Data

Part B: Graphing GLOBE Data

  1. Display the Default Graph: Maximum Air Temperature.
    • Be sure Reynolds High School is still checked (see Part A). The default graph will be maximum temperature unless you select a different column for which the school has data. Let's look at maximum temperature measurements for Reynolds school. Above the list of schools, choose Make a Graph in the green box and click on Go.
      Link on the GLOBE Web site that creates a graph or other data requests.

  2. Look carefully at the graph you made. Then answer the Checking In questions.

    Graph: 1996 through 2003; maximum air temperature; Greenville, PA



    Checking In

    • The Maximum Air Temperature is showing somewhat of a repeating pattern here. What do you think the reason for this is?
    • Is the pattern similar to one you might expect to see for maximum air temperature in your own city or town? If not, what are the differences?


  3. Change the Time Frame of the Graph to Two Years.
    • Below the graph, there is a box labeled, "Graph Data and Display Section". In the left side of that box, change the upper YYYY date from 1995 to 1998. Change the MM date from 10 to 01. Leave the DD date at 01. This will change the starting date of the graph to January 1, 1998. In the lower date box, change the ending date of the graph to December 31, 1999.
    • Below the section of the screen where you can change the time frame of the data displayed in the graph, change the size of the graph from small to large. At the bottom of the box, click the Redraw button.
      GLOBE tool for selecting parameters to display in a graph

    You now have just two years of maximum temperatures on the screen—all of 1998 and 1999—and you may see that each day is represented by a small red triangle.

  4. Look carefully at the two-year graph. Then answer the Checking In questions.

    Graph: 1998 and 1999; maximum air temperature; Greenville



    Checking In

    • Look at the temperature scale, which runs along each edge of the graph. On approximately what date does the highest maximum daily temperature occur in 1998? When does it occur in 1999?
    • Compare the two years and describe the differences and similarities you see.

  5. Add Data for Soil Moisture (10 cm) to the Graph.
    • In the CURRENTLY SELECTED DATASETS menu, be sure that Maximum Temperature is still highlighted. Then, holding down the Command-Shift keys (Mac) or Control key (PC), scroll down to Soil Moisture (10 cm) and highlight it. Click Redraw.
      GLOBE tool for selecting parameters to display in a graph


      • You should now have two data sets that appear in the graph. Soil moisture content is defined in terms of weight. It is a measure of the weight of water that exists in a gram of soil. Notice that the scale along the right side of the graph has changed. The unit of measurement for soil moisture is gram/gram, or g/g.

  6. Save and print your graph.
    • With your cursor over the graph itself, use Control -> Click (Mac) or Right Click (PC) to open a menu and save the image to the disk. Rename the image and save it in a new folder. Now re-open the image and print it.

  7. Look carefully at the graph of Maximum Temperature and Soil Moisture (10 cm). Then answer the Checking In and Stop and Think questions.

    Graph: 1998 and 1999; maximum air temperature, soil moisture; Greenville



    Checking In

    • During which months does soil moisture at 10 cm remain basically steady?
    • During which months does soil moisture at 10 cm change quite frequently?
    • What change do you notice as you compare soil moisture for 1998 with 1999?


    Stop and Think

    1: Do air temperature and soil moisture at 10 cm follow the same pattern? Why or why not?
    2: What does this graph show about the interconnection between air temperature and soil moisture at 10 cm?


  8. Add Data for Soil Moisture (90 cm) to the Graph
    • Holding down the Command-Shift keys (Mac) or Control key (PC), and making sure that Maximum Temperature and Soil Moisture (10 cm) are still highlighted, highlight Soil Moisture (90 cm). Change the Data (Y) Axis Range to Use a fixed range, and click Redraw.
      GLOBE tool for selecting parameters to display in a graph


  9. Look carefully at the new graph. Then answer the Checking In questions.

    Graph: 1998 and 1999; maximum air temperature, soil moisture; Greenville



    Checking In

    • In what ways is the graph of Soil Moisture (90 cm) similar to the graph of Soil Moisture (10 cm)?
    • In what ways are the two Soil Moisture graphs different?
    • How does the 1998 graph compare with the 1999 graph for soil moisture at each depth?

  10. Add Data for Rainfall to the Graph.
    • Holding down the Command-Shift keys (Mac) or Control key (PC) and making sure that all three sets of data are still highlighted at the top of the list, scroll down to Rainfall and highlight it. Make sure the option for the Data Axis Range is Use a fixed range, and click Redraw.

    • Download, rename, and save the image. Now re-open the image and print it. You may want to use colored pencils to highlight the different data sets.

    • Look carefully at the new graph. Then answer the Checking In questions. Notice that a new scale has been added to the right of the graph, and that the unit of measurement is mm for millimeters of rain.There is now a lot of data crowded into a small space. In Part C you will get a closer look at the details.


    Graph: 1998 and 1999; maximum air temperature, soil moisture, precipitation; Greenville



    Checking In

    • Look at the rainfall data for both years. Do you think that Greenville, PA has a rainy season?
    • Is there a rainy season where you live?

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