Part 4: Examine Arctic Temperature Trends

Elders at a Community meeting

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. Once you click the "Create Timeseries" button, wait a few seconds while the data are prepared for you.

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?

5. You'll copy the data of interest to bring it into Excel. In your browser, select the rows of data for 1978 through 2006 then Edit > Copy.

Show me the selections

Hide

1. Launch Excel and create a new workbook.
2. Click cell A1 then Edit > Paste.
3. Choose Data> Text to columns to spread this Fixed width data into separate cells across the worksheet.
   Show me the details of how to import and prepare the data
   Hide

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

   
   
4. Insert a blank row at the top of your spreadsheet and add appropriate labels for each column.
   Show me how to create a new row
   Hide

   
   

   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 month of November from 1978 through 2006.
   Show me the details of how to generate this graph
   Hide

   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.
      Show me the new spreadsheet
      Hide

      
   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—2006.
   5. Add a linear trendline to your graph. Click your graph, then choose Chart > Add trendline and click the Linear option.
   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.