Secondary circulation

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A secondary circulation is a circulation induced in a rotating system. For example, the primary circulation of Earth's atmosphere is zonal. If however a parcel of air, that moves in a purely zonal direction, is accelerated or decelerated zonally, the Coriolis force will add a meridional component to its velocity. This meridional circulation is then the secondary circulation.

Zonal and meridional

The terms zonal and meridional are used to describe directions on a globe.

Coriolis force A force on objects moving within a reference frame that rotates with respect to an inertial frame.

In physics, the Coriolis force is an inertial or fictitious force that seems to act on objects that are in motion within a frame of reference that rotates with respect to an inertial frame. In a reference frame with clockwise rotation, the force acts to the left of the motion of the object. In one with anticlockwise rotation, the force acts to the right. Deflection of an object due to the Coriolis force is called the Coriolis effect. Though recognized previously by others, the mathematical expression for the Coriolis force appeared in an 1835 paper by French scientist Gaspard-Gustave de Coriolis, in connection with the theory of water wheels. Early in the 20th century, the term Coriolis force began to be used in connection with meteorology.

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