Flux

flux

1. The rate of flow of some quantity, often used in reference to the flow of some form of energy.

   
   

   
   See also power.

   
   
2. In the field of atmospheric turbulence and boundary layers, often used as a contraction for flux density; namely, the flow of a quantity per unit area per unit time. These fluxes can be defined in two forms: dynamic and kinematic. The dynamic flux of a quantity is the flow of that quantity per unit area per unit time, where often the word dynamic is assumed if it is not explicitly stated. The advantage of a kinematic flux is that it has units that are more easily measured by a conventional meteorological instrument. The units are usually a velocity (m s^-1) times a temperature (K), specific humidity (kg_water/kg_air), or wind speed (m s^-1).