Characterization of Spatial Variability Structure of Solute Transport in Soils Using Geostatistics

本研究應用地理統計技術解析土壤中 溶質傳輸之空間變異，並與美國伊利諾大 學自然資源暨環境科學系合作，取得土壤 中溶質傳輸實驗之分析調查資料，供本計 畫執行研究之用。在本計畫中，地理統計 的半變異圖和克利金法被用來分析推估溶 質於土壤中隨土層深度不同的空間變異性 結構和濃度的空間分佈。地理統計推估溶 質的空間分佈是依據溶質於土壤中分佈的 空間變異結構，如果溶質分佈的空間結構 有明顯的空間相依性，則推估所得之空間 分佈便能表現溶質於土壤中傳輸過程的空 間連續性，並可免除原始調查資料中較多 測定分析誤差的干擾，適合進一步用於溶 質傳輸模式的分析模擬。Geostatistical techniques were used for analyzing the spatial variation of solute transport in soils. A data set crated from the field study in the department of Natural Resource and Environmental Science, University of Illinois, U.S.A. was used for assessment. In this study, the semivariogram and kriging were used to analyze the spatial variation structure and estimate the spatial distribution of solute concentrations for various soil depths. In geostatistics, the kriging technique is based on the spatial structure shown in a semivariogram. As the semivariogram model for solute concentrations shows obviously spatial dependence, the spatial distribution estimated by kriging will include the spatial continuity of solute transport in soils. The kriging estimate can prevent the inference of measurement errors. Thus, kriging estimated values are more suitable than original observed values to be used for modeling solute transport