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Sources of Turbulence


Notes:

The air operates much the same as that turbulent pool of water. Earlier we discussed how air masses are large bundles of air that only reluctantly mix with each other. The same thing happens on the micro scale. In this case the proper term is air parcels. The air around us is made up of thousands of air parcels. Each parcel may be blown by the wind, rise if it is less dense then the surrounding parcels, sink if more dense, heat or cool, etc.

You are looking through this soup of moving air parcels. If these air parcels differ in temperature, density, or moisture content then they will refract light differently. Good Seeing occurs when all of the air parcels are the same. I will simplify these differences to the single term “turbulence” since turbulence is a byproduct of these differences.

In the next few slides we will characterize some of the main sources of turbulence.