In 1948, C. Warren Thornthwaite presented his original and unique models for potential evapotranspiration (PE) and the climatic water budget. Although his initial intent was focused on development of a world-wide classification of climate, Thornthwaite, J.R. Mather, and many other climatologists applied these models to a variety of hydroclimatic applications, including the development of climatic indices for the evaluation of relative "wetness and dryness" of various places, estimating regional-scale runoff from the continents, determining trends in hydroclimatic variability, and applied applications in agriculture, human health and comfort, building design, industry commerce, and engineering.
On the silver anniversary of Thornthwaite's original publication, the climatic water budget is alive and well in hydroclimatological research. Although more sophisticated models for watershed and agricultural modeling now exist, they are based on the Thornthwaite's original climatic water budget and are used to evaluate climate variability and address applied research questions. A perusal of introductory physical geography and earth science textbooks, however, suggests declining attention to water-budget concepts at both high school and college levels. This paper illustrates PC- and UNIX-based examples of water budget applications for enhancing educational objectives as well as providing near real-time monitoring of climatic variability and analyzing environmental problems in applied climatology