Flux tower

Since July 1998, fluxes of carbon dioxide (CO2), sensible heat (H), latent heat (LE), and momentum (w) have been measured at 20 Hz intervals over 30-minute periods, at a height of 12 m (approximately 6 m above the canopy of the dominant tree species). The setup includes a three-dimensional sonic anemometer (Solent-R2 from 1998 to 1999, then Gill-R3 from 2000 to 2014) and an infrared gas analyzer (LI-6262), both sampling at a frequency of 20 Hz. Flux data are processed following the methodology described by Aubinet et al. (2000).

Since 2014, all equipment has been upgraded to meet the requirements of the European ICOS infrastructure. A three-dimensional sonic anemometer (HS-50 – GILL) and an infrared gas analyzer (LI-7200) have been installed as part of the eddy covariance system. A system for measuring the gradient of CO2 and H2O concentrations complements this setup at different heights on the tower. This vertical gradient is measured using another analyzer (LI-840A).

Several micro-meteorological sensors are also installed on the tower. Their purpose is to measure and monitor various climatic and environmental variables on a local scale, particularly above the vegetation canopy. These sensors collect data that are essential for better understanding weather conditions and local phenomena such as convection.

In 2021, in collaboration with the company ACRI-ST and as part of the ESA/COPERNICUS LAW project (“Copernicus Space Component Validation for Land Surface Temperature, Aerosol Optical Depth, and Water Vapour Sentinel-3 Products”), two infrared radiation thermometers (Heitronics KT15II model) were installed at 12 m to measure vegetation canopy temperature.

More recently, in 2023, as part of the BIOMASP+ project (genic emissions, chemistry, and impacts in the metropolitan area of São Paulo), a prototype for Relaxed Eddy Accumulation (REA) measurements was installed and tested to prepare for a campaign measuring VOC (volatile organic compound) fluxes.

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