ES 331/767 Exercise V MODERN CLIMATE OF KANSAS James S. Aber

## Temperature record

Long-term, relatively complete temperature data are available for many cities in Kansas. The oldest comes from Leavenworth, beginning in the 1820s, but this record has several gaps in data coverage. Since the 1870s, most cities have relatively continuous weather records; modern records are normally obtained at the city airport. Older data through 1946 were compiled by Flora (1948); data since 1946 are published in the Climatological data annual summary for Kansas of the National Climatic Data Center. The data include monthly average temperatures and mean annual temperatures for cities and airports in all parts of the state.

National Climatic Data Center--NCDC.

These temperature data reveal that significant short-term and long-term changes in climate have taken place in Kansas for the period of record.

## Exercise

The exercise is based on the temperature record for Manhattan, Kansas--see temperature data. Each student will calculate and graph simple statistical values from the temperature data.

• Calculate decade average values for January (winter), July (summer), and annual mean temperatures. Round off your decade average temperatures to whole F°. Note: some decades are missing one or two years of values.

• Calculate long-term average values for January, July, and annual mean temperatures using all available data for (a) 1860 through 1899, and (b) 1900 through 1999. Average all years of data; do not use decade averages. Round off your average temperatures to whole F°.

• Calculate total average values for January, July, and annual mean temperatures using all available data: 1860 through 1999. Average all years of data; do not use decade averages. Round off your average temperatures to whole F°.

• Prepare one or more graphs to illustrate the average values calculated in steps 1, 2 and 3. Plot temperature values on the vertical axis and years on the horizontal axis. Use of graph paper (or computer graphing program) is recommended.

Compare your results to the Plant Hardiness Zone Map--see Fig. V-1. Also see the revised map at the National Arbor Day Foundation (2006) and historical maps from the Arnold Arboretum of Harvard University (Del Tredici 1990). Compare these with the 2012 version from the USDA, and note differences. Answer the following questions.

1. What is the climatic basis of the plant hardiness zone map?

2. What is the current plant hardiness zone for Manhattan, Kansas? What was Manhattan's plant hardiness zone for the previous (1990) map?

3. What general changes in plant hardiness zones took place since the 1920s for the central United States?

## Results

Based on your analysis of the temperature record, prepare a written summary in which you discuss the short- and long-term history of temperature for Manhattan, Kansas. You should attempt to answer the following questions.

• What are the warmest and coldest individual months, years, and decades?

• Is there any clear long-term trend for increasing or decreasing temperature?

• Are changes in annual mean temperature more affected by winter or summer conditions?

• Did temperature conditions change noticeably during the 19th century?

• Did temperature conditions change noticeably during the 20th century?

• How does the plant hardiness zone map relate to climate in the late 20th century?

• Based on your personal experience, how does this record compare with the early 21st century?

You should ultimately determine if there is any evidence for climatic warming during the early, middle or late 20th century. Does the temperature record correspond to your previous personal knowledge of past climate in Kansas or the Great Plains?

Historical climate of Kansas by Dorian J. Burnette.

## Turn in

• Statistical values for decade and century temperatures.
• Graphs showing temperature variations.
• Short report of your findings.

## Reference

• Del Tredici, P. 1990. The new USDA Plant Hardiness Zone Map. Arnoldia 50/3, p. 16-20.
• Flora, S.D. 1948. Climate of Kansas. Kansas State Board of Agriculture, Report, vol. 67, no. 285, 320 p.