Modèle climatique intégré aux décisions à portée environnementale

CONT: Wind erosion models have been used to assess policy impacts on soil erosion, but validation of models has been difficult until recently. We evaluated the Environmental Policy Integrated Climate (EPIC) wind erosion submodel by comparing simulation results to field measured wind erosion sediment losses. Using standard model inputs and actual wind velocities, wind erosion was simulated for a field near Lethbridge, Alberta where field measurements of wind erosion were made in April 1992 on a Dark Brown Chernozemic soil. The EPIC submodel predicted erosion losses for each day that erosion was measured, and approximated the magnitude of erosion on 6 of the 7 erosion events. EPIC significantly overestimated erosion for one event and also simulated erosion on 3 days when no erosion was recorded. Field length had a larger effect on simulation results during large erosion events than for smaller events. The effect of surface soil water content on wind erosion appeared to be captured by the model, but only limited data were available to evaluate this aspect. Other portions of the model such as the effects of surface roughness and vegetative cover could not be evaluated in this study.