CESAR, the Cabauw Experimental Site for Atmospheric Research, is the Dutch focal point for collaboration on climate monitoring and atmospheric research and is situated on the KNMI meteorological research site near Cabauw in the Netherlands. CESAR addresses challenging topics in atmospheric research, especially the questions that are related to the interaction between clouds, aerosols and radiation and questions dealing with land-atmosphere interaction. These topics are approached via process studies, model evaluations, climate monitoring, development of new experimental techniques and supporting activities for satellite missions. For each of these approaches, specific demands are put on the instrumentation, mode of operation and overall infrastructure. This paper gives an overview of CESAR that was recently augmented with a scanning drizzle radar (IDRA) and a multi-wavelength Raman lidar for aerosols, clouds and water vapor (CAELI).