Question

What is the meaning of eddy covariance?

Answer 1

Eddy covariance is a technique used in environmental physics and meteorology for measuring the transfer of various properties like heat and gases between the atmosphere and the earth's surface, based on the analysis of turbulence and fluctuations.

Step-by-step explanation:

The term eddy covariance is commonly used within environmental physics and meteorology to describe a technique for measuring and calculating the transfer of heat, water vapor, gases, and other scalar entities in the atmosphere. This method involves analyzing the covariance of vertical wind velocity with the corresponding scalar quantity's fluctuation over a period of time. The principle behind eddy covariance relies on the natural turbulence in the atmosphere, where 'eddies' or small air parcels mix and transport properties like heat and moisture.

An analogy for understanding eddies in the context of electricity is eddy current, which refers to circular currents induced within conductors by a changing magnetic field, as frequently observed in electromagnetic applications. Similarly, the working principle of electric generators, where mechanical work is turned into electric energy, involves an electromotive force (emf) induced by rotating a coil within a magnetic field. This induced emf allows the generator to produce electricity.

Answer 2

Eddy covariance is a micrometeorological method used to measure vertical turbulent fluxes in the atmosphere, utilizing the concept of eddy currents which relate to the workings of an electric generator. It helps in understanding the exchange of gases like carbon dioxide between the Earth's surface and the atmosphere.

Step-by-step explanation:

The term eddy covariance is a method utilized in micrometeorology to measure and calculate vertical turbulent fluxes within the atmosphere. This method makes use of eddy currents, which are loops of electrical current induced in conductors when there is a change in magnetic field due to the motion of the conductor or the change in magnetic field itself, known as motional electromotive force (emf).

The eddy covariance technique is analogous in some ways to the workings of an electric generator, which is a device that converts mechanical work into electric energy by inducing an emf through the rotation of a coil in a magnetic field. However, within the context of eddy covariance, the fluctuations of these eddies are measured to determine the exchange of gases like carbon dioxide between the Earth's surface and the atmosphere.

In practical terms, the eddy covariance method involves measuring the components of wind velocity and the concentrations of gaseous constituents simultaneously and at a high frequency. By correlating the upward and downward velocities (the eddies) with the gas concentrations, researchers can infer the net exchange of gases across the surface-atmosphere boundary. This information is vital in understanding ecosystem gas exchange processes and in assessing the impact of various factors like climate change on these processes.