The knowledge on turbulent exchange above rough surfaces becomes increasingly important, because attempts are made to model dispersion processes close to forests or cities. There is especially a lack of knowledge on turbulence characteristics in canopies of sparse and indermediate density.
		The data from the Rio Frio Tower provides vertically high resoluted information on turbulent exchange mechanisms within and above such a sparse canopy. The setup is designed for the study of vertical divergences of sensible heat, CO2 and H2O fluxes.
		The 20m high triangular lattice tower supported 9 ultrasonic anemometers (CSI CSAT3) and 5 CO2/H2O open path analyzers (LICOR 7500). All raw data was synchronously dumped to an industrial computer and a datalogger.
		Just around tree top the vertical resolution of the measurements were enhanced. This is the region, where highest gradients were supposed to be measured.
		Prior to the tower measurements, all open path analyzers had been intercompared.< BACK

2004 Photos by Andreas Christen, Institute of Meteorology, Climatology and Remote Sensing, University of Basel