Sensitivity analysis of the soil-water-evaporation module of the E-DiGOR (Evaporation and Drainage investigations at Ground of Ordinary Rainfed-areas) model is presented. The model outputs were generated using measured climatic data and soil properties. The first-order sensitivity formulas were derived to compute relative sensitivity coefficients. | Research Article Turk J Agric For 34 (2010) 497-507 © TÜBİTAK doi: Sensitivity analysis of the evaporation module of the E-DiGOR model Mehmet AYDIN1,*, Suzan Filiz KEÇECİOĞLU2 1 Department of Soil Science, Faculty of Agriculture, Mustafa Kemal University, TR-31040, Hatay - TURKEY 2Technical Training College of Antakya, Mustafa Kemal University, TR-31040, Hatay - TURKEY Received: Abstract: Sensitivity analysis of the soil-water-evaporation module of the E-DiGOR (Evaporation and Drainage investigations at Ground of Ordinary Rainfed-areas) model is presented. The model outputs were generated using measured climatic data and soil properties. The first-order sensitivity formulas were derived to compute relative sensitivity coefficients. A change in the net solar radiation significantly affected potential evaporation from bare soils estimated by the Penman-Monteith equation. The sensitivity coefficients were positive, with a mean value of . The sensitivity of potential soil evaporation to soil heat flux was lower during the summer months and higher during the winter. The gradient of saturated vapour pressure–temperature curve increased or decreased the potential evaporation rates because of the occurrence of the gradient variable in both the numerator and denominator of the equation. Increases in the vapour pressure deficit increased the evaporation and its effect was more pronounced in the winter. In the case of aerodynamic resistance, the coefficients were constantly negative, and became more negative in the winter, which means a negative correlation between the input and output. In Aydın’s equation, the dependent variable (actual soil evaporation) was initially very sensitive to a change in the water potential of a wet soil. The sensitivity decreased progressively during the drying period. The coefficients related to the absolute values of soil water potential were constantly negative, with a mean value of –. The .
