advection

[prettygoodword]

advection (ad-VEK-shun) - n., a horizontal flow, especially one that transports heat, moisture, particulates, etc.


Distinguish from convection, which is a vertical circulation. Both are concern of meteorologists. Both are as well from Latin -- or in the case of advection, coined from Latin roots in the early 1900s -- from vehere, to carry or bring plus a prefix: ad- meaning toward or con- meaning with.

---L.

Comments

[packbat.livejournal.com]

How odd. In the technical jargon of heat transfer, "advection" is the motion of heat in a fluid by bulk motion of the fluid, where "convection" is motion of heat by bulk motion and diffusion combined, regardless of direction.

[prettygoodword.livejournal.com]

Hmm -- my recollection from thermodynamics class is that we treated convection as bulk circular flow, regardless of direction, while treating diffusion separately. In those terms, I was thinking of advenction as bulk flow with source(s), as opposed to just circular. (Gah, I can't believe how much vector calc I've forgotten, that I can't just rattle off the right terms here.) Faulty memory or difference between how physics and other fields use terms? -- you decide.

I'm not surprised the meteorology treats these things differently, though.

---L.

[packbat.livejournal.com]

I mean, if you want the calculus, I can tell you the calculus - the differential equation governing convection is

∂T/∂t = v·∇T + ∇·(k∇T)

and the first term on the right side is advection and the second conduction i.e. diffusion. If the meteorologists use the terms differently, I'm quite surprised.