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Advection (from Latin advectare = to move up, to get) generally refers to the approach of things and is often used synonymously with flow transport.

In the English-speaking world, convection is divided into advection as a directional flow transport and diffusion, which takes place at the atomic level and is non-directional .

Advection in Meteorology

In meteorology , the term advection is used in connection with the approach of air masses ; H. with the horizontal movement of the air . One speaks of temperature advection , a horizontal special case of convection when the wind vector has a component in the direction of the temperature gradient . This means that the air drawn in has a different temperature than the air that is drawn out. If, on the other hand, the wind blows perpendicular to the temperature gradient and thus parallel to the isotherms , then the advection is zero. In principle, the properties of a fluid can be determined by advection, i. H. be transported continuously with the large-scale current. For example, when warm air is advected, it becomes evenly warmer everywhere in the area under consideration.

In contrast, convective transport takes place more discreetly, so to speak in packets : Warm air bubbles rise through the colder ambient air. Reason: the earth's surface is approximately horizontal and therefore the light air heated on the ground is initially under the cold, heavy air.

Advection in gliding

Also called freedom from advection. If there is advection of cold air, long distances can be traveled. It is recognized by the fact that the wind turns to the left as the altitude increases. The warm air advection is the opposite.

Advection in other geosciences

In hydrology and geology , advection refers to the transport of a substance dissolved or suspended in the water with the flow of the water, i.e. with its mean speed and direction.

See also

Individual evidence

  1. ^ Advection - Physics School. Retrieved August 25, 2019 .
  2. ^ Klussmann, Niels author: Lexicon of aviation . ISBN 978-3-662-54039-8 , pp. 13 .
  3. ^ Advection - Physics School. Retrieved August 25, 2019 .