A Study on Identification of Homogeneous Regions for Reference Evapotranspiration

• Main Author: 吳冠廷
• Other Authors: Ching-Tien Chen
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/43342352147176073972

碩士 === 國立嘉義大學 === 土木與水資源工程學系研究所 === 99 === Food security is an important international issue especially during periods of relatively rapid climate change. Timely and appropriate irrigation not only ensures good crops yields, but also effectively improves the utilization of water resources. Therefore, rapid and accurate estimation of reference crop water requirements, providing water for agricultural irrigation project and operational management of simulation, is the pressing priorities of researchers who engaged in agricultural water. According to the data of artificial weather stations and automatic weather observation stations in western Taiwan which are main grain production areas and prone to lack of irrigation water, self-organizing map(SOM), Ward's method and K-means method are used to group the gauges into specific clusters base on the average temperature, maximum temperature, minimum temperature, wind speed, station elevation and UTM coordinates in cluster analysis. Finally, the coefficient of variation (CV) and the range are used to test whether regions may be acceptable as being homogeneous. The results show that the SOM cannot identify the homogeneous regions more accurately. Therefore, it is observed that the 40 meteorological stations in western Taiwan can be grouped into 5 clusters according to the two-dimensional density map resulting from SOM. The homogeneous regions are delineated after the reference evapotranspiration is estimated for each station using Penman-Monteith method. Then, the map of regional reference crop water trends for western Taiwan can be established. The proposed approach is expected to be served for irrigation water allocation and water resources planning and management.