EARTH SYSTEM SCIENCE
WRITING ASSIGNMENT #11 - THE 1997-98 EL NINO EVENT
So, we've spent plenty of time examining the wealth of Earth System data documenting the present El Nino (warm phase) event and the very cool computer graphics used to illustrate various phenomena. I originally had intended to have you download images and create animations as we had done with other data sets all semester. But our efforts would pale in comparison to some of the images already available on-line at NOAA and NASA websites. So, the dilemma was to come up with something unique for our El Nino exercise this week. Here it is
You will recall that I mentioned to you last week that there was a positive correlation of El Nino events and exceptional harvests of French wine grapes. Well, this week you will have an opportunity to see if I was right or just full of...Chardonnay.
This week we will visit the World-Wide Web Home Page of the legendary Chateau Haut-Brion in the Bordeaux region of France. Here, they have archived data related to the quality of their harvest for the past 100 years (to 1899). Our task this week will be to compile data from their description of the wine harvest and compare these descriptions to known El Nino/La Nina or transitional years since 1944. Then, we will see if there is a correlation of fine wine vintages and El Nino or not (at least for the last 50 years).
YOUR ASSIGNMENT FOR THIS WEEK:
Here's what to do:
1. First, set up a spreadsheet in Microsoft Excel so you will be able to tabulate your data. In order to do this effectively, it would be a good idea to examine the manner that the data are recorded on the Chateau Haut-Brion site first and make some decisions about which data you want to record.
2. You can get to the Chateau Haut-Brion site be clicking on the button below.
3. Once at the Chateau Haut-Brion, you can begin speaking with a fake French accent and learn much about the history of their wine-making operation (which dates to the 16th Century!). You can also access their "Vintage" archive to determine which years were the best during the preceding century. Start your search by entering "1998" in the search window and clicking the "Search" button. Note the the 1998 vintage has not yet been given an assessment - the proprietors warn you not to drink this wine for 7 years. So, we cannot fully assess the quality of this year, though the printed description suggests that over all this will be a very good wine (maybe "Very Good" would be a reasonable grade for this vintage).
4. To access the description of the first year in their data base, type "1899" in the box and click the button. Note that the year advances to the next one automatically. Now we need to make some decision regarding how we will quantify these designations in the spreadsheet. Perhaps we can make a scale by assigning numbers to the different descriptive titles. For example, anytime they refer to a year as "Poor", we could assign a numerical value of 0 to that year. Thus, you will need to cycle through the years to determine the complete variety of descriptions they use. Then you will need to rank these terms and assign numerical values to them. Do this somewhere on your spreadsheet.
5. On your spreadsheet, create a column with each year dating from 1998 to 1944 (why 1944? wait and see). In the next column, you may wish to include the verbal description of that year's harvest. In the next column, insert the numerical value of those words (0 for poor, for example).
6. When you have compiled all the years, calculate the average (or mean) value of the yearly grape harvests. Create another column where you will subtract this mean value from the observed value for each year - this will result in a number called a "residual about the mean" - obviously, sometimes a yearly value will be greater than the mean, and sometimes the yearly value will be less than the mean (which produces a negative number).
7. Examine only those years for which the residual is positive (i.e. observed - mean > 0). Note the year and copy these years to a separate column. Now, we need to determine which of these years (if any) were El Nino years. To do this, we can consult a table from one of your readings for last week. Go to the report on climate patterns associated with El Nino at the Center for Ocean-Atmosphere Prediction Studies at Florida State University. Table 2 of this booklet contains a list of cold phase, warm phase and transitional phase years of ENSO dating back to 1944. Compare the list of warm phase years to those of your better-than-average wine harvests. Do they compare favorably? Do they compare unfavorably? Was is correct to attribute exceptional wine harvests to El Nino years? How good is the correlation? Can it be refined? Suppose you exclude years which are "Very Good" and examine only exceptional years. Does the correlation improve or get worse? Is my credibility damaged or in tact as a result of this exercise?
8. Describe your findings and mail both your spreadsheet and written response to me. You might also try to create a graphic to illustrate your answers if you can think of a simple way to visualize your data.
CHATEAU HAUT-BRION COAPS EL NINO BOOKLET
