The Ogallala Agro-Climate Tool

A Visual Basic™ agro-climate application capable of estimating crop evapotranspiration and irrigation demand over the Ogallala aquifer region is described here. The application's meteorological database consists of daily precipitation and temperature data from 141 U.S. Historical Climatology Network stations during 1976–2005. From that daily data the program calculates climate and crop evapotranspiration (ETc) statistics over arbitrarily defined periods within summer or winter growing seasons at user-selected latitude–longitude coordinates. The statistics reported include: estimates of seasonal and sub-seasonal ETc derived from the FAO-56 single crop coefficient algorithm, probabilities of exceedance of cumulative rainfall, irrigation demand and growing degree days, the probability that minimum and maximum daily temperatures will exceed user-defined temperature thresholds, and the probability of heat stress, cold stress and dry periods of varying duration.

Research highlights▶ Crop ET and irrigation demand over the Ogallala aquifer region. ▶ Based on data from 141 high-quality meteorological stations during 1976–2005. ▶ Climate and crop ET statistics over any period of the year at any location.