Advection: Difference between revisions

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==Distinction between advection and convection==
The term ''advection'' often serves as a synonym for ''[[convection]]'', and this correspondence of terms is used in the literature. More technically, convection applies to the movement of a fluid (often due to density gradients created by thermal gradients), whereas advection is the movement of some material by the velocity of the fluid. Thus, somewhat confusingly, it is technically correct to think of momentum being advected by the velocity field in the Navier-Stokes equations, although the resulting motion would be considered to be convection. Because of the specific use of the term convection to indicate transport in association with thermal gradients, it is probably safer to use the term advection if one is uncertain about which terminology best describes their particular system.
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An example of convection is flow over a hot plate or below a chilled water surface in a lake. In the ocean and atmospheric sciences, advection is understood as horizontal movement resulting in transport "from place to place", while convection is vertical "mixing". <ref>David A. Randall, "General circulation model development", Academic Press, 2000. [https://books.google.com/books?id=pRibtFBDNDAC&pg=PA648&dq=advection+and+convection#v=onepage&q=advection%20and%20convection&f=false (Google books)]</ref><ref>Scott Ryan, "Earth Science (CliffsQuickReview)", Wiley Publishing Inc., 2006. [https://books.google.com/books?id=PV_BabxTTkcC&pg=PA99&dq=advection+convection&lr=&as_drrb_is=q&as_minm_is=0&as_miny_is=&as_maxm_is=0&as_maxy_is=&as_brr=0#v=onepage&q=advection%20convection&f=false (Google books)]</ref> Another view is that advection occurs with fluid transport of a point, while convection may be considered as fluid transport of a vector.
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==Meteorology==