In this computer exercise, students will compare and contrast satellite and ground data for temperature in northern California over several decades and extract trends about climatic regions for wine-grape production. The satellite data, which we provide in an Excel spreadsheet, contains four 1° blocks along a longitudinal transect from the coast of California to the mountains. The ground based data in the spreadsheet are from four weather stations (Ft. Bragg, Napa County Hospital, University of California at Davis, and Colfax), each representing one of the blocks along this transect. For each block and station, we calculated the Winkler Scale, a technique for classifying the climate of wine growing regions in which geographical areas are divided into five climate categories based on degree days. Plotted are changes in the Winkler Scale for the four blocks and stations over time.
Students can use the data provided or go to the NASA sites to choose their own blocks or weather stations plug the numbers into the spreadsheet and calculate the Winkler Scale for other locations. They can plot the Winkler Scale over time and analyze the plots and what they imply about premium wine-grape production.
Students should learn something about:
- longitude and latitude and map reading.
- (optional) downloading data from online NASA databases and pasting them into a spreadsheet.
- degree days and its relationship to plant growth and development.
- spatial resolution and temporal longevity of data
- data smoothing and trend analysis
- wine quality
CONTEXT FOR USE
This activity is appropriate for undergraduates or older, particularly those who have previous experience with computer spreadsheets. Using the data provided and its analysis places little demand on the students. Extending this analysis to other locations would require additional time and computer resources (e.g., a computer with an internet connection and an Excel compatible spreadsheet program).
Exercises and Downloads
All of the readings and materials are available online:
Students can follow the complete example for a longitudinal transect across northern California or they can download from the NASA websites for Surface meteorology and Solar Energy data and Ground station temperature data and follow the same procedures for another location in the United States.
The students will need an introduction about degree days and its use for all sorts of practical guidelines including the design of buildings as well as crop development.
Assessments may include:
- Students can suggest methods such as running averages to evaluate trends in other noisy data sets.
- Students can find longitude and latitude for other locations.
REFERENCES AND RESOURCES
Resources and Further Reading
- NASA’s Surface meteorology and Solar Energy data used here.
- Ground station temperature data used here.
- 2nd edition of Winklers et al. (1974) book on general viticulture. Preview with Google books in which climate and vineyard location are discussed..
- Article compares satellite and ground station temperature data for agricultural purposes.
- Article for the general public with interviews with grape figures.
- Presentation at Whitman College 2007 highlights the changes in the West coast (PDF).
- PNAS 2006 scientific article treats the entire United States.
- General article on wine quality.