1.
What
is standard sea-level pressure in millibars? In inches of
mercury?
In pounds per square inch?
A. Standard sea level air pressure is 1013
mb
(millibars), which is the same as 29.92 inches of mercury or 14.7
pounds
per square inch.
2. Mercury is 13 times heavier than water. If you built a
barometer
using water rather than mercury, how tall would it have to be to record
standard
sea-level pressure (in centimeters of water)?
A. Standard sea level pressure in
centimeters
equals 76 cm of mercury. Thus, the height of standard sea level
pressure
if a water barometer is used would be 13 times higher, or 988 cm.
3. Describe the principle of the aneroid barometer.
A. An aneroid (without liquid) barometer
consists
of evacuated metal chambers that compress as air pressure increases and
expands
when air pressure decreases.
4. What force is responsible for generating wind?
A. The pressure gradient force causes winds
to
blow. Winds blow from higher pressure to lower pressure; the
bigger
the pressure difference, the greater the wind speed.
5. Write a generalization relating the spacing of isobars to the
speed
of wind.
A. Closely spaced isobars indicate a strong
wind;
widely spaced isobars indicate a light wind.
6. How does the Coriolis effect modify air movement?
A. The Coriolis effect (the deflective
force
of Earth's rotation) causes air to be deflected to the right of its
path
of motion in the Northern Hemisphere and to the left in the Southern
Hemisphere.
7. Contrast surface winds and upper-air winds in terms of speed
and
direction.
A. Upper air winds generally parallel the
isobars,
the result of the pressure gradient force and the Coriolis effect
balancing
one another. However, near Earth's surface, friction slows the
winds.
Since the strength of the Coriolis effect is proportional to the
wind
speed, the Coriolis effect is diminished. Consequently, the
Coriolis
effect can no longer offset the pressure gradient force, and the
surface
winds blow at an angle across the isobars.
8. Describe the weather that usually accompanies a drop in
barometric
pressure and a rise in barometric pressure.
A. A drop in barometric pressure
usually
leads to rainy or stormy weather. A rise in barometric pressure
usually
indicates clear skies.
9. Sketch a diagram (isobars and wind arrows) showing the winds
associated
with surface cyclones and anticyclones in both the Northern and
Southern
hemispheres.
A. see diagram 16.8, pg. 448.
10. If you live in the Northern Hemisphere and are directly west
of
the center of a cyclone, what most probably will be the wind direction?
What
will the wind direction be if you are west of an anticyclone?
A. The winds west of a cyclone in the
Northern
Hemisphere would be northwest, and winds west of an anticyclone would
be
southeast.
11. The following questions relate to the global pattern of air
pressure
and winds?
a) The trade winds diverge from which pressure zone?
A. The trade winds diverge from the
subtropical
highs
b) Which prevailing wind belts converge in the stormy region
known
as the polar front?
A. The westerlies and polar easterlies
converge
in the polar front.
c) Which pressure belt is associated with the equator?
A. The equatorial low pressure belt is
associated
with the equator.