Vadose zone model uncertainty as conditioned on geophysical data.

An approach to estimating the uncertainty in model descriptions based on a landscape space to model space mapping concept is described. The approach is illustrated by an application making use of plot scale geophysical estimates of changes in water content profiles to condition a model of recharge to the Sherwood Sandstone Aquifer in the United Kingdom. It is demonstrated that the mapping is highly uncertain and that many different parameter sets give acceptable simulations of the observations. Multiple profile measurements over time offer only limited additional constraints on the mapping. The resulting mapping weights may be used to evaluate uncertainty in the predictions of vadose zone flow dynamics for the site

Avaliação de dois simuladores para predição da lixiviação de sulfona de aldicarbe em um Latossolo Vermelho-Amarelo Evaluation of two simulators to predict the leaching of aldoxycarb in a red-yellow latossol

Este trabalho teve por objetivo o estudo da lixiviação de sulfona de aldicarbe em um Latossolo Vermelho-Amarelo, na região de Lavras, MG, para posterior comparação com os resultados obtidos pelos simuladores CALF e PESTLA. Os resultados mostraram alta lixiviação de sulfona de aldicarbe no solo em estudo. Aos 44 dias após a aplicação do inseticida e com uma lâmina de água acumulada de 241,4 mm, a quantidade média de sulfona de aldicarbe remanescente nas colunas de solo de 45 cm de profundidade foi equivalente a 17,92% (±5,88) da dose aplicada, enquanto os simuladores CALF e PESTLA estimaram 20,52% e 37,82%, respectivamente. O simulador CALF gerou melhores estimativas da quantidade média de sulfona de aldicarbe no perfil do solo nas diferentes datas de amostragem, enquanto o simulador PESTLA gerou melhores estimativas da distribuição do inseticida ao longo do perfil do solo, nas diferentes datas de amostragem.<br>This work was carried out to study the leaching of aldoxycarb in a Red Yellow Latossol in Lavras, Minas Gerais State, Brazil, and to compare the observed results with those obtained by the simulators CALF and PESTLA. The results showed a high leaching of aldoxycarb in the soil. After 44 days of the insecticide application and with 241.4 mm of accumulated water applied in each column, the remained quantity of aldoxycarb in the soil columns (45 cm long) was 17.92% (±5.88) of the initial applied rate. However, the simulators CALF and PESTLA predicted 20.52% and 37.82%, respectively. CALF simulator gave better predictions of the overall mean residue concentrations of aldoxycarb, and PESTLA simulator gave better prediction of residues distribution