Accuracy of Reference Evapotranspiration Estimation by Two Irrigation Controllers in a Humid Climate

作者：Rutland D C; Dukes M D^*

来源：Journal of Irrigation and Drainage Engineering, 2014, 140(6): 04014011.

DOI：10.1061/(ASCE)IR.1943-4774.0000720

• Reference evapotranspiration (ETo)
• Humid region
• Hargreaves
• Smart controller
• Irrigation
• Penman-Monteith

Increasing municipal water demand has led to new innovations in water-saving technology. Evapotranspiration-based irrigation controllers, also known as weather-based irrigation controllers, are a technology that use evapotranspiration (ET) estimates to schedule irrigation. Although real-time on-site data collection could help improve data quality, limited data parameters collected or simplified reference evapotranspiration (ETo) estimation methods from an on-site sensor could potentially have an impact on estimated ETo values for stand-alone controllers. Conversely, collection of data from off-site weather stations that are not representative of the local conditions could lead to inaccurate ETo estimations for local irrigation sites. The Weathermatic SL1600 and Toro Intelli-sense controllers were selected for testing because of the different methods of data collection and ETo estimation. This study was conducted in two locations: Wimauma and Gainesville, Florida. In Wimauma the Weathermatic controller significantly overestimated ETo compared to on-site ETo estimates using the ASCE-EWRI standardized method (ETo) by 9-15% for the duration of the study, while ETo sent to the Toro controllers was similar to on-site ETo estimations (1-3%) for the duration of the study. However, the Weathermatic controller overestimated ETo for every season (fall: 5-8%; winter: 6-8%; spring: 11-16%; summer: 22-25%), and the Toro controller overestimated ETo in the summer seasons (12%) and underestimated ETo in the winter seasons (17%). In Gainesville, the Weathermatic and Toro controllers both overestimated ETo compared to on-site ETos (30 and 10%, respectively). However, when compared to ETos using data from the Gainesville National Oceanic and Atmospheric Administration (NOAA) weather station, the ETo of the Toro controller was consistent with the equation and location of the weather data that were likely used by the weather service to calculate ETo, indicating that this was likely the data source for the ETo sent to the Toro controller. Overall, ETo sent to and used by the Toro Intelli-sense controllers was closer to on-site ETo estimations than that which was estimated by the Weathermatic SL1600 controllers on site.

• 出版日期2014-6-1