Examination of the Surface Renewal Technique for Sensible Heat Flux Estimates in Screenhouses

摘要

Screenhouses are widely used to reduce direct radiation and wind speed and increase humidity and water savings. The increasing area of screenhouses requires a reliable method for estimating the crop évapotranspiration. Direct methods like the Eddy Covariance (EC), remain both expensive and dependant on complex data analysis and corrections. This limits their day-to-day usage in the farm level. An alternative, low cost and simple to use technique is the Surface Renewal (SR). The SR technique utilizes high frequency (typically about 10 Hz) temperature readings, by miniature thermocouples, which allow the estimation of the sensible heat flux through a calibration factor. Additional simple measurements of other energy balance components enable the estimation of evapotranspiration as a residual. The aim of this research is to investigate, for the first time, the applicability of the SR technique in estimating the sensible heat flux in screenhouses.