Heat Transfer Mechanism

There are three mechanisms by which heat (energy) is transferred in the atmosphere:

1. radiation
2. conduction
3. convection

Let's consider each of these individually.......







Conduction
* Heat transfer through molecular motions
* from warm to cold
* consider a metal bar
* Heat transfer through molecular motions
* from warm to cold
* Heat transfer through molecular motions
* from warm to cold
* Other examples of conduction??
* What is an atmospheric example of conduction??

Conductivity: materials ability to transfer heat by conduction.




Convection

* Transfer of heat through mass movement of a substance
* the "substance" could be air or water
Atmospheric Convection

* What are examples of convection in the atmosphere?
* thermals -->>
* consider a hot parcel of air near the ground
* Q: what is the parcel going to do?
* A: it's going to rise - a thermal is formed
* thermals generate turbulent motions near the ground - noticable during takeoff/landing in airplanes
* Q: when is the best time for thermals to form?
* A: During Mid afternoon When the ground is Hottest.
* If the thermal is vigorous enough, it will often form a cloud and sometimes grow into a thunderstorm.
* Hence, thunderstorms are often referred to as "convection"
* Other examples of convection?



Radiation
* Radiant energy - the transfer of energy via electromagnetic waves.
* examples:
o sun warms your face
o apparent heat of a fire
o others?
* Q: Using the three mechanisms for heat transport that we just discussed, show with a diagram how a thunderstorm can form.