University of Twente Student Theses


Reference Crop Evapotranspiration spatially interpolated and temporally distributed in Java

Ensing, E. (2009) Reference Crop Evapotranspiration spatially interpolated and temporally distributed in Java.

[img] PDF
Abstract:As the water scarcity in the agricultural sector increases, there is a greater demand for more efficient irrigation. With better predictions of the reference crop evapotranspiration (ETo), more efficient irrigation scheduling can be done. The is the evapotranspiration rate from a reference surface, which resembles a uniform surface of green grass with adequate water. In this study a model has been made for determining the on Java. This model can calculate the interpolated at a certain location when the coordinates and the predicted wind speed at that location are given. These calculations can be carried out for each month and the average over the year. The grid size of the interpolation is 1 by 1 minute, which is about 1.84 by 1.84 kilometers. For this study, data from 24 measurement stations on Java have been used. For 20 of these stations, the data has been supplied by the Food and Agriculture Organization of the United Nations (FAO). For the remaining 4 stations, the data has been supplied by the Indonesian National Agency for Meteorology, Climatology and Geophysics (BMKG). Also, altitude data from GEBCO has been used. In this research, five methods have been used for predicting the . In each of these methods the is interpolated. Method 1 consists of interpolating the values calculated with data from the measurement stations, using triangle-based interpolation methods. In Method 2 the is divided into an aerodynamic and a radiation component, which are individually interpolated. In this method, the wind speed is partially excluded from these components, which means the given or predicted wind speed is used to calculate the . In Methods 3, 4 and 5 the is divided into four components representing the aerodynamic part, the radiation part, the psychometric constant and the saturation vapor pressure relationship. Here the wind speed is entirely excluded from these components. In Method 3 the psychometric constant is interpolated, in Method 4 it is calculated using the altitude data from GEBCO and in Method 5 it is calculated using the altitude given in the data from the measurement stations.
Item Type:Essay (Bachelor)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering BSc (56952)
Link to this item:
Export this item as:BibTeX
HTML Citation
Reference Manager


Repository Staff Only: item control page