Lessivage des polluants urbains et changement climatique : l’influence des modèles

Rainfall for the next century will be influenced by global warming. These modified rainfalls will have influences on rainfall runoff. In order to analyze these impacts, this study compared different buildup and washoff functions with several future rainfall series. These series of rain were first simulated with the Bartlett-Lewis method to disrupt the distribution of rainfall events in winter and summer. Then, the delta factor method has been applied to modify the intensity of rainfall under different scenarios of emissions. Three emissions scenarios were tested (A1B, A2 and RCP3PD) and for each of these scenarios, three estimates of the results (2.5th, 50th and 97.5th percentiles) were considered depending on the chain of General Circulation Models (GCM) and Regional Climate Models (RCMs) used. It was found that concentrations of leached pollutants are particularly susceptible to washoff functions and empirical parameters included in these functions. Disruption of rainfall also influences the leached concentrations in summer and winter. The emissions scenario has very little impact on levels instead of percentiles that play an important role in their distribution. The type of washoff function and the choice of GCMs and RCMs are important elements to evaluate the influence of climate change on pollutants washed into urban areas.