What is Eddy Covariance System?
The Eddy Covariance (EC) system is based on two fundamental elements, the first is the wind with its direction and speed components, and the second, the concentrations of the gases that move in it. The wind is composed of eddies (eddy) that carry a concentration of gases, for the purpose of the study refers to CO 2, and water vapor. Knowing the direction, speed and concentration of the gases in the eddies, the flow of the gases studied can be determined (Burba and Anderson, 2005). To determine the area of influence (data capture) of the EC system, two terms are used: footprint, which is used to define the effective distance at which the equipment is taking readings and is dependent on wind speed. Therefore, this distance is variable and can range from a few meters after the tower to the fetch, a term used to denote the maximum distance in a straight line (parallel to the ground) at which the equipment can record information, this parameter is determined by the installation height of the equipment, in a ratio of 1-100, that is, for one meter of height 100 horizontal meters. Behind this simplification of the technique there is a scaffolding of mathematical models of the physical and meteorological order, which allow the development of calculations to accurately estimate the flow of CO2 and water vapor.
Why do we use it?
The measurements of the mentioned parameters are performed with robust and sophisticated equipment, which must be installed on a structure (scaffolding, tower or antenna) that exceeds the height of the ecosystem under study. It is necessary, as a minimum, to have a sonic anemometer and a gas analyzer. Additionally, it is important to collect micrometeorological data such as: radiation, latent flux, ambient temperature, ambient humidity, soil moisture and soil temperature, among others. In this way, the Eddy Covariance system is being strengthened and, of course, generating more accurate information.
Download Data
Data downloads will soon be available on the AmeriFlux website.
New AVA Eddy-Flux tower on Barro Colorado Island
The Eddy flux tower, referred to as “New AVA” was established in January 2019 to replace the old AVA tower that was dismissed in August 2017.
Featured publications
Detto, M., & Pacala, S. W. (2022). Plant hydraulics, stomatal control, and the response of a tropical forest to water stress over multiple temporal scales. Global Change Biology, 28, 4359–4376. https://doi.org/10.1111/gcb.16179