Part 4—Examine Arctic Temperature Trends

Step 1 –
Obtain Temperature Data

Elders at a Community meeting, August 2007.



sea ice near the shore
Sea Ice along the shore near Baffin Island, August 2007, another record minimum year.


At the meeting with the elders, students share the news of their findings with the local community and begin a discussion. During the discussion, Dr. Meier questions, "We've seen that the ice extent during Novembers is decreasing, but do you know why? Has the temperature of this region been rising so it is above the freezing point for more days of the year than it used to be?" He suggests turning to NOAA's Earth System Research Laboratory (ESRL) Climate Analysis Branch to view and download monthly and seasonal averages for a variety of climate data.

To compare the sea ice measurements you made with the average temperatures in the Arctic region at the same time, you'll work with time series data—monthly average temperatures that correspond to the same time periods as the Sea Ice Index data.

  1. Open this link to the ESRL Monthly Time Series temperature data (will open in a new window).
  2. On the page, select the first Dataset, "NCEP/NCAR Reanalysis monthly means" (the default) and click the "Go to Selection Options" button.
  3. To obtain the surface air temperatures for Hudson Bay, enter the bounding values shown in the screen shot below into the fields of the dialog box.
  4. temperature re-analysis settings


  5. Once you click the "Create Timeseries" button, wait a few seconds while the data are prepared for you.
  6. The tabular data (rows and columns) you've just opened show monthly mean temperatures for the Arctic region from 1948 to the present. Each row is a different year, and the separate columns represent the months January through December.

    Take a quick look at the data: figure out which is usually the warmest month of the year. Which month is coldest?

  7. Next, copy the data of interest to bring it into Excel. In your browser, click and drag to select the rows of data for 1978 through present then choose Edit > Copy.
Select rows for 1978 through 2006

Step 2 –
Analyze Temperature Data in Excel

  1. Launch Excel and create a new workbook.
  2. Click in cell A1 then select, Edit > Paste.
  3. Once the data is pasted into Excel, choose Data > Text to Columns... to spread this fixed width data into separate cells across the worksheet.

    • In the Browser window, copy the data for the years 1978-2006.
    • Open Excel and choose File > New Workbook.
    • On the spreadsheet, click in cell A1 and choose Edit > Paste
    • Under Data, choose Text to Columns...
      text to columns

    • The text to columns wizard is in three steps. In each case, choose the defaults.

    text_to_columns wizard1
    text_to_columns wizard2
    text_to_columns wizard3

  4. Insert a blank row at the top of your spreadsheet and add appropriate labels for each column.
    1. In Excel, select row 1 then choose Insert > Row
    2. Label the columns in your new row - Year, January, February, etc.
  5. Make an XY (Scatter) graph with a trend line to show average temperatures in the Arctic region for the months of November from 1978 through present.
    1. Copy the "Year" Column; paste it to a new sheet in your workbook.
    2. Copy the "November" temperature column; paste it in a column next to the year column in your new sheet.
      year vs November temp
    3. Select the two columns of data, Year and Temperature, and click the chart wizard button or choose Insert > Chart....
    4. Create an XY (scatter) graph of November temperatures vs. Year from 1978 to present.
    5. Add a linear trendline to your graph. Click on the November series line your graph, then choose Chart > Add Trendline... and choose the Linear option for your trendline Type.
    • What does your trendline say about November temperatures from 1978 to 2006? Describe the relationship shown by your trendline.
  6. Click your graph and copy it in Excel.
  7. Open the word processing document in which you pasted the Sea Ice Extent graph and paste your November Temperatures graph next to it.
    • Describe the relationship you see between the 2 datasets.
  8. Optional: Save and print your graphs of sea ice and temperature trends.

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