Due to the major role of the sun in heating the earth’s surface, the atmospheric planetary boundary layer over land is inherently marked by a diurnal cycle. The after-noon transition, the period of the day that connects the day-time dry convective boundary layer to the night-time stable boundary layer, still has a number of unanswered scientific questions. This phase of the diurnal cycle is challenging from both modelling and observational perspectives: it is transitory, most of the forcings are small or null and the turbulence regime changes from fully convective, close to homogeneous and isotropic, toward a more heterogeneous and intermittent state