"O wild West Wind, thou breath of Autumn's being,
Thou, from whose unseen presence the leaves dead
Are driven, like ghosts from an enchanter fleeing....
"Of the dying year, to which this closing night
Will be the dome of a vast sepulchre,
Vaulted with all thy congregated might
"Of vapours, from whose solid atmosphere
Black rain, and fire, and hail will burst: oh, hear!"
Ode to the West Wind, Percy Bysshe Shelley, via LoudLit.org
"...Til day rose; then under an orange sky
The hills had new places, and wind wielded
Blade-like, luminous black and emerald,
Flexing like the lens of a mad eye...."
Wind, Ted Hughes
"Air Pressure and Wind"
John P. Stimac, Department of Geology/Geography, Eastern Illinois University College of Sciences
"We know that standard atmospheric pressure is 14.7 pounds per square inch. We also know that air pressure decreases as we rise in the atmosphere.
"1013.25 mb = 101.325 kPa = 29.92 inches Hg = 14.7 pounds per in2 = 760 mm of Hg = 34 feet of water...."
There's quite a bit more about air pressure. Quite informative, too.
Then the page turns to wind:
"...Wind results from a horizontal difference in air pressure and since the sun heats different parts of the Earth differently, causing pressure differences, the Sun is the driving force for most winds.
"The wind is a result of forces acting on the atmosphere:
- "Pressure Gradient Force (PGF) - causes horizontal pressure differences and winds
- "Gravity (G) - causes vertical pressure differences and winds
- "Coriolis Force (Co) - causes all moving objects, such as air, to diverge, or veer, to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
- "Friction (Fr) - very little effect on air high in the atmosphere, but more important closer to the ground.
- "Centrifugal Force (Ce) - objects in motion tend to travel in straight lines, unless acted upon by an outside force.
All of which is rather technical.
ComparisonsWhich helps the reader understand wind?
The Lemming thinks the answer is - both.
But not the same sort of understanding.