In Higher Spheres: 40 years of observations at the Cabauw Site

In 1964 the need for high measuring masts for studying the dispersion of air pollution and the wind climate was discussed at KNMI and estimates were made of the funds needed. This led to the construction of an 80 m high mast in the city of Vlaardingen in the highly industrialized area near the city of Rotterdam. Using the expertise developed in Vlaardingen, the Cabauw-mast was designed and built. A continuous measurement programme with analogue data registration was started on October 26, 1972. In the following years new and better instruments were installed including advanced remote sensing systems in the last 20 years. The development of digital data registration techniques and the increasing data storage capacity allowed the operation of much larger observational programmes, so that new and challenging research themes could be tackled. Cooperation with other research institutes and with universities led to the establishment of CESAR (Cabauw Experimental Site for Atmospheric Research) in 2002. CESAR has developed into a high-tech observatory with an international reputation and plays a key-role in various international research programmes and networks on regional and global scale. The measurement programme comprises the physical and chemical aspects of the entire atmospheric column and its interaction with the earth surface.

In this report we review the technological developments and the research themes that were developed at Cabauw in the past 40 years.