Program 4 - Temperature Anomoly

In this program, we'll look at some climate change data from the National Oceanic and Atmospheric Administration (the US government agency in charge of weather and climate data, among other things). In particular, we'll look at one of the "headline" datasets, global temperature anomoly over the last century. By "anomoly" they just mean the difference between the annual average temperature and an single baseline temperature. In this case they use the average from 1900-2000 as a baseline (although the data goes from 1880-2012).

They use an average as the baseline, rather than a single year, because the temperature varies from year to year. If you average over a number of years these variations smooth out. If you average over a century, the result is just one number and you can't see any trend at all.

Our program will caluclate a moving average of the temperature anomoly data. We'll let the user enter an integer k. Then for each year we calculate the average of the k years before, the year itself, and the k years after. that year. For instance, if the user picked k=3, for the year 1936 we would average the temperatures for 1933, 1934, 1935, 1936, 1937, 1938 and 1939. Remember that to average seven numbers, we add them up and divide the sum by seven.

Our program will let the user experiment with averaging over different time intervals, to get a nice balance between smoothing out annual variation and losing the trend entirely.

Requirements

Your program should ask the user for the number of years over which to average, and either exit or keep asking if it does not get an integer between 0 and 60.

The output of your program should be a file called movingAvg.csv. The ending .csv means that unlike the input file, the output data is separated by commas. This allows programs like Microsoft Excel, or Google Docs, or the ManyEyes Website from IBM, to read the data and make a chart. You are required to hand in a chart (as a screenshot) as well as your program.

After you get your program running, try a few different choices of k, make some charts, and see which you think best presents the data.

Example output

Step By Step

This is a big enough program that you can't just type it in and hope it will work. We will break it down into two big steps, and submit the results of the first step on Tues 25 and the results of the second step on Thurs 2/7.

• For practice, make a list containing 5 integers, and then write a while loop that computes the average of the five integers. Save this little program; it will be the basis for the second loop in your program.
• Now start your program. Let the user pick the integer k. Use the inputCheck.py module to help check the user's input number. Make sure it is between 0 and 60.
• Make a while loop that reads in the data file, and prints out every line.
• Change the block under the while so that it uses the strip() and split() methods to get only the temperature for each year, and just prints that out. Change temperature to a floating point number.
• Instead of printing out the floating point numbers, store them as a list in your program. Lets say the list is called tempList.
• Make your program print out tempList. Then submit this program, using SmartSite, as "Program 4 checkpoint".

• Start your second while loop by going through tempList from beginning to end, and printing out each temperature.
• Now change the block under the while so that it only runs through tempList[k] through tempList[-(k+1)] and prints them out.
• Now change it so that for each list element it hits, it prints out the average of the k items before it, the element itself, and the k items after it. Use the little practice program you wrote in the first week as a guide.
• Add a year to your output, so that instead of printing just the temperature, it prints the year, a comma, and then the average temperature for the time interval surrounding that year. Notice that the data starts with year 1880.
• Now instead of printing out the years and averages, write them to file movingAvg.csv.
• To make a chart, one way is to use Google Drive; if you have Excel or some other spreadsheet program that can make a chart, feel free to use that instead. To do it in Google Drive, go to Google in a Web browser, and click on Drive on the black menu bar at the top (you may need to make a free Google account). Upload your file movingAvg.csv (with the upload icon just to the right of the red "Create" button on the left), right-click (Windows) or control-click (Mac) on it to Open with... Google Sheets. Now you're in the spreadsheet program. You can select Insert->chart to make the chart. The "Use column A as labels" should get the years onto the bottom of the graph.

What to Submit