The Cabauw Experimental Site for Atmospheric Research (Cesar) has been established in 2002. It is a consortium of presently nine institutes and universities in the Netherlands. The goal of the consortium is to operate and maintain at the Cabauw site a unique observational facility with a comprehensive set of remote sensing and in-situ equipment to characterize the state of the atmosphere, its radiative properties and the interaction with the land surface. The principal use of the measurements is 1) to study physical and chemical processes, 2) climate monitoring and 3) to perform validation studies.
The Cabauw tower itself is owned by KNMI, the Royal Meteorological Institute of the Netherlands. Cabauw tower (4.927° E, 51.971° N, -0.7m ASL) is a steel structure that rises up to 213 m above ground level. It is located in the center of the Netherlands about 25 km southwest of the city of Utrecht. The direct surroundings of the tower have a relatively low population density, although the towns within 100 km of the tower contain a population or more than 7 million people. Main land use of the area around Cabauw is a mixture of intensively and extensively managed grassland. Two km south of the tower one arm of the river Rhine (local name Lek) meanders through the landscape.
South of the tower the rivers have deposited loam and clay on the topsoil since the last ice age, on top of the peat layers that also developed since then. This post-glacial peat layer covers most of the remaining direct area. On the clay soils in the river areas quite some (fruit) orchards are located. In general the terrain is very flat with ground levels at or just below sea level (0 to -2 m ASL). A small town of about 1500 inhabitants (Lopik) is located 1 km east of the tower.
The tower itself consists of a 2 m diameter steel pipe. On the inside an electric elevator takes about half of the available space, the remaining space contains a ladder and internal platforms every 2.5 m. The tower is equipped with external platforms every 20 m. Each platform is connected to three booms for mounting equipment. Each boom can be lifted by a hydraulic mechanism for easy instrument mounting and maintenance from the platforms. Meteorological observations of standard parameters like windspeed, temperature and humidity are taken at all levels using equipment on all three booms; depending on wind directions data is selected for minimal interference of the tower structure on the measurements (Van Ulden & Wieringa, 1996).
More information can be found on the following links:
CESAR website (currently out of order)
ICOS Nederland
ICOS Europe
KNMI
ECN
