Evaluation de techniques d’interpolation spatiale de la pluie en milieu urbain pour une meilleure gestion d’événements extrêmes : le cas du Grand Lyon

Evaluation of rainfall spatial interpolation methods in urban area for a better management of extreme rainy events : the case of the urban area of Greater Lyon

Abstract

Rainfall spatial interpolation techniques are numerous and their use and efficiency are variable. The choice of one or the other depends on the aim of the study, but also on the territorial context of the area (surface, network density, etc.). The purpose of this study is to determine the most adequate rainfall interpolation technique for a small scale area, depending on their efficiency and practical use. Four interpolation techniques, determinist or stochastic, have been evaluated on a specific place, Greater Lyon urban area. Interpolations show significant differences according the techniques used, but these differences do not come from the nature of method (determinist or stochastic). In addition, Greater Lyon characteristics, like the high network density, explain that a basic interpolation method provides results nearly similar, and sometimes better, to complex methods. Thanks to the evaluation of the interpolation methods, the first interpolation analyses provide information in order to characterise rainfall distribution and extreme events over the urban area.