ANALYZING HISTORICAL CLIMATOLOGY RECORDS IN INTRODUCTORY GEOSCIENCE

A simple exercise of manipulating the NDP-041 Historical Climatological Network data set using Microsoft Excel not only exposes students to the types and applications of climatological data but also builds students’ confidence in constructing and interpreting graphs.

The NDP-041 data set (download from ftp://cdiac.esd.ornl.gov/ndp041 or see http://cdiac.esd.ornl.gov/ to order CD-ROM format), from the Carbon Dioxide Information Analysis Center, contains records of total monthly precipitation in tenths of millimeters for 7533 stations worldwide and mean monthly temperature in tenths of degrees Celsius for 6039 stations worldwide. Since these data span the period from 1693 (1701 for temperature) to 1990, their temporal and spatial distributions include times and places affected by global climate change (including the Little Ice Age and twentieth century global warming) and “regional,” short-term changes (such as the Dust Bowl). Therefore, entry-level undergraduates can begin to evaluate these issues by applying Excel’s basic statistical tools to NDP-041 data.

Questions to guide the exploration of global warming include: a) Has the earth been warming? b) If so, is the warming rate steady over time? and c) Is warming uniform over the globe? Investigation of the Dust Bowl is facilitated by these questions: a) What happened climatologically during the Dust Bowl years? and b) Were heat and dryness confined to the classic “Dust Bowl” area of the High Plains or were the climate changes broader in scope? In answering these questions, students use Excel to calculate and plot yearly mean temperatures, total annual precipitation, and 5- and 10-year moving averages of temperature and precipitation for individual stations. Working in small groups, students analyze these plots for short- and long-term variations in temperature and precipitation, considering the correlation between precipitation and temperature in creating drought conditions. Students archive their findings and present them to the class, exposing all the students to climate data from a wide distribution of stations. Students gained confidence in their ability to interpret graphs and to communicate their findings. They also synthesized analyses of climate data and first-hand accounts of the Dust Bowl into original theses about the cause of the Dust Bowl.