Last Monday, 1 March 2021, a start was made building a new tower at the Loobos site. The existing tower was build in 1995 out of thin, light-weight aluminum as one of the first ecosystem sites in Europe. Loobos is now one of the sites with the longest period of record! In the meantime, the trees have grown up to the height of the tower, which therefore has become too low for ICOS standards of Eddy Covariance measurement height. The tower was also quite difficult to climb. Therefore a new tower is being constructed out of steel scaffolding equipment.
The new tower
The new tower will have a base of 2.57m × 2.57m and become 36m tall, which is 16m above the canopy. It will have stairways for easy access. There will be platforms at several heights to accommodate installation of equipment.
Preparation
The start of the construction phase marks a milestone worth celebrating! The preparation took much time for requesting permits from the municipality, finding a supplier and construction firm who could also fix the guy wires. The municipality requested detailed construction calculations and drawings too, which made it an iterative process.
Housing and mains power
Just before the construction of the tower a sea container was located at the site, which will serve as storage for computer and measurement equipment and a workplace to prepare for fieldwork and to verify the data collected. Additionally, Liander has installed a power cable to supply 380V power.
What is next?
The construction of the tower will be finished by next week. Afterwards, a fuse box will be installed (with lightning protection) and a 230V power cable will be drawn into the tower. After then, the tower is ready for installation of instrumentation. The Meteorology and Air Quality department of Wageningen University will install Eddy Covariance equipment to measure CO2, water vapor and sensible heat fluxes, radiation components, meteorological sensors as well as sensors for soil temperature, moisture and ground heat flux.
The exact setup will be discussed with the ICOS-Ecosystem Thematic Centre in order to prepare Loobos for labelling as a Class 2 Ecosystem site in the European ICOS infrastructure.
Utrecht University will install instruments to measure VOC fluxes and TU Delft will install DTS (Distributed Temperature Sensing) equipment. These measurements are made as part of the Ruisdael Observatory. In addition, RIVM will measure NH3 fluxes at Loobos. The installation process will be made in steps. We aim to have the Eddy Covariance equipment installed by May and the meteo and soil equipment by summer.
More information
With the new facilities, the Loobos tower provides chances for long-term measurements as well as shorter experimental campaigns. The site is part of the Ruisdael Observatory and in principal open for partners of the Ruisdael consortium and other interested groups. Please contact PI Michiel van der Molen for more information.
Top left: the new tower; top middle: the new tower with in the background the old one; top right the anchor points for the guy wires. Bottom: the sea container as housing construction
