Model Of Real-time Evapotranspiration Based On Meteorological Data For Open Field

In this study of the thesis, following the Soil-Plant-Atmosphere-Continue consideration, a real time model for estimating soil evaporation and crop transpiration, that is driven by automatic weather station data and underlying surface crop and soil parameters, has been formed by using numeric calculation method. Such model is derived from energy balance approach of soil and canopy, as well as simulation of the important parameters. Using the ground-truth weather data, the modeling results of field evapotranspiration, latent heat and sensible heat are compared to a real-time observation by eddy correlation measurement. The studied result yields conclusion as: the model has higher sensitivity to simulate the field evapotranspiration, and can illustrate the temporal and spatial regime of the field evapotranspiration in detail. The comparison of modeling and measuring data suggests that the model has also higher accuracy and tendency against the measured truth. In addition, the model has high precision, real time and continuity. Compared to the eddy correlation measurement, the modeling precision reduces due to an uniform treatment of the crop canopy. However, such approach improves the applicability of the model. The question here exists as: although the th fetch length attains the demand of 100 instrument height, it is still unknown if it attains the theoretic condition of the mixing underlying surface. Such may causes error and has difficulty to find literatures for reference, and also need to be studied further. Nevertheless, since the model only need few crop and soil parameters to drive, the perfectly modification will make it useful in modeling regime of field evapotranspiration, as well as canopy and soil temperature for different near-ground boundary layer.