Download CHAPTER 11: STREAMS AND FLOODS

CHAPTER 14: THE ATMOSPHERE II
1. The pressure exerted by the weight of
an underlying column of air above is
atmospheric pressure.
2. Air density is determined by
measuring the mass of atoms and
molecules of nitrogen, oxygen, and other
gases per volume of air.
3. Air contracts when cooled, generating
higher pressures. Air expands when it is
warmed, generating a decrease in air
pressure.
4. Air pressure decreases rapidly at
lower altitudes where air density is
greatest.
5. Compressed air becomes warmer;
expanding air becomes cooler.
6. Adiabatic changes occur without any
loss or gain of energy to or from the
surrounding air.
7. A rising parcel of air cools for two
reasons: (1) it is expanding and cooling
because of decreasing air pressure, and (2)
it is moving farther away from the warm
surface of Earth.
8. The adiabatic lapse rate is 10 oC per
1,000 m (10 oC/km; 29 oF/mile) for dry
(unsaturated) air.
9. An average value for the wet
adiabatic lapse rate is 6 oC/km (18
o
F/mile).
10. To form a cloud droplet, water vapor
must have a surface upon which to
condense.
11. Clouds are composed of billions of
tiny water droplets that eventually combine
to form rain, snow, or hail.
12. Cloud droplets fall, colliding with
other droplets and combining with them, a
process called collision-coalescence, to
form raindrops.
13. Air temperatures over much of Earth
fall below freezing within a few kilometers
of Earth’s surface in the lower portion of
the troposphere.
14. The mechanism whereby rain drops
are formed from melting ice is called the
Bergeron process.
15. Miniature ice crystals act as
condensation surfaces and gradually
increase in size to form snowflakes.
16. Warm air will rise through the stable
air as long as the temperature of the parcel
of warm air remains higher that of the
surrounding air.
17. Orographic lifting (also called
topographic lifting) occurs when air is
forced to rise over an obstruction in the
landscape, typically a mountain range.
18. The rain shadow effect occurs where
precipitation is relatively rare.
19. Air above Earth’s surface inherits the
thermal characteristics of the underlying
surface.
20. Wind is the horizontal movement of
air that arises from differences in air
pressure.
21. Winds represent moving air as it
flows from areas of high pressure to areas
of low pressure.
22. Wind direction refers to the direction
from which the wind originates rather than
where it is going.
23. The greater the contrast in pressure,
the steeper the gradient will be and the
faster the wind will blow.
24. The closer the isobars are together,
the greater the pressure drop with distance
and the faster the wind speed.
25. Winds will be deflected to the right of
their course in the Northern Hemisphere.
26. Winds blowing parallel to isobars are
termed geostrophic winds.
27. Wind blowing near Earth’s surface is
slowed by frictional drag from the surface.
28. A counterclockwise airflow, known
as a cyclone, forms around a low-pressure
center. A clockwise flow of air is known as
an anticyclone.
29. Rising air in low-pressure systems
becomes cooler and may reach saturation,
resulting in clouds and rain.
30. Air descends in high-pressure zones,
warming as it approaches Earth’s surface.