Le climat urbain de l'agglomération lilloise: Configuration spatiale et variations temporelles de l'îlot de chaleur urbain

Work performed within the Laboratoire de géographie des Milieux Anthropisés during the last five years make it possible to get a better knowledge of both the spatial distribution and temporal variations of the nocturnal «heat island» of the Lille metropolitan area. Conventional fixed meteorological measurements (from Météo-France and belgian I.R.M.) are too scarcely distributed for mapping the urban heat island. Several campaigns of running measurements have been used and show a very stable spatial configuration of the heat island, in close relationship with the urban building features. Conventional measurements have been used to investigate the link between the intensity of the heat island and meteorological daily conditions. In winter and in summer as well, intense heat islands are related to «radiative conditions», with weak winds and clear sky, whereas cloud cover, strong winds and rain lead to the weakening or vanishing of heat islands.