STORM2K

Hi,

I take this for other post in the 94L topic, and I want to know for you guys what is the difference between convection and convergence?

Convection is the key. Convection will generate convergence

Thanks in advance.

The straight definitions:

CONVECTION -- Motions in a fluid that transport and mix the properties of the fluid. These properties could be heat and/or moisture. When used to imply only upward vertical motion, it is then the opposite of subsidence.

CONVERGENCE -- Wind movement that results in a horizontal net inflow of air into a particular region. Convergent winds at lower levels are associated with upward motion. Contrast with divergence.


In this situation, convection is being used to describe a cumuliform event, such as rainshowers and/or thunderstorms. Convergence is used to discuss the "inward" motion of air near the surface. Surface convergence and low pressure go hand-in-hand.

Therefore, to translate: Thunderstorms are the key. Thunderstorms will help generate the low pressure center.

the thunderstorms aren't even a requirement. By its definition, convection could simply be the rising thermals. As the air rises from the surface, it greats low pressure due to the net outflow. Therefore, air must fill this void. This is accomplished by the low level air converging on the area of low pressure at the surface.

The other side of the equation DOES have to do with thunderstorms. Thunderstorms release latent heat of condensation. This causes thickness values to increase, resulting in high pressure aloft and low pressure at the surface (this is how hurricanes are maintained).

Thanks senorpepr and wall_cloud for the answers!

When I went to college, the word convection was usually seen with 'conduction' and usually, in transport phenomena class, had to do with heat transfer. Senorpepr's definition isn't too radically different from the college definition, actually.

To add on to what has already been said, there is a significant difference between how meteorologists tend to use the word "convection" and how other fluid dynamicists use it, but usually at the end of the day we are all talking about the same thing. In general fluid dynamics, convection is used to describe macroscale motion of fluid transporting some fluid property (such as temperature) in any direction. In meteorology, we usually split this up into advection and convection, with advection describing horizontal motions, and convection describing vertical motions. This is only because horizontal motion of fluid in the atmosphere is often different in what it "accomplishes" than vertical motion, so it's useful to have two different words to describe them.