I am having a hard time understanding this?

Question

Hey can someone explain this to me?
The decrease in temperature coupled with the low density of the air in the mesosphere (about 1 gm-3; at the stratopause, or a thousandth of the density at sea-level, to 100 times less at the mesopause) means that the mesosphere includes both turbulence and atmospheric waves which have a wide range of spatial and temporal scales. Such motions are important not only because of the mixing of chemicals that occur as a result, but also because the mesosphere is the region of the atmosphere where spacecraft on re-entry start to feel the background wind structure, rather than just aerodynamic drag. Some of the small-scale waves drive an average seasonal flow upwards from the lower summer polar mesosphere across the equator and down deep into the winter polar stratosphere.

I am having a hard time comprehending it, thank you!

http://library.thinkquest.org/21418/spac...

Answer 1

The mesosphere is an area of reduced temperture an pressure which causes waves in the air, which vary in size over a wide range, and also vary in the rate at which they "wave". This air motion causes mixing of chemicals present in the air, and an incoming spacecraft will first encounter changing air flows for the first time. Before that, the only effect of air was drag, which acts only in the direction of motion, but in the mesosphere it will experience sideways forces for the first time. The smaller waves, rather than being completely random and averaging out, will provide a net wind that moves air from the pole which is having summer toward the pole that is having winter.

Answer 2

this whole thing can be summed up in a sentence. an incoming object from space will be encountering varying atmospheric challenges at different equatorial locations.
I think....
and bye the way I could not look at the site provided, they said it is gone

Answer 3

good luck
thx for the 2 pts.