AgriMet: Automated Weather Observations for Evapotranspiration Modeling

Competition for limited water resources in the western United States continues to increase. To this end, the Bureau of Reclamation and Bonneville Power Administration partnered to create a network of automated agricultural weather stations - called AgriMet - in the Pacific Northwest in the 1980's. These stations collect and telemeter the meteorological parameters required to model crop evapotranspiration (ET). The network started with three stations in 1983, but has since grown to over 60 stations in Reclamation's Pacific Northwest region, 22 stations in the Great Plains Region in western Montana, and seven stations in the Mid Pacific region. These automated weather stations transmit their data hourly by the GOES satellite, and the information is used in the Kimberly-Penman 1982 evapotranspiration model to compute reference ET at each station. Crop coefficients are then applied to estimate water use for specific crops grown at each station for every day of the growing season. Use of AgriMet information in irrigation scheduling results in water and energy savings, reduced soil erosion, and protection of surface and ground water supplies. Near real time hourly weather data from AgriMet is also used for a variety of applications, including peak power load forecasting, agricultural frost protection, and short term weather forecast verification.