Download Centrifugal Force and Coriolis Steps to draw the general winds on

Centrifugal “Force” and Coriolis “Force”
Physics
If you are riding in a car and go around a curve, you will likely feel that there is a
force pushing you toward the side of the car on the opposite side of the curve’s
direction. As we have studied, when going around a curve there is a force acting
toward the center of the curve, called the centripetal force, not a force acting away
from the center. The apparent force that pushes you on the side of the car away
from the curve’s center is due to inertia. As the car goes around the curve, by
Newton’s First Law you want to keep going straight. In doing this, you have an
encounter with the side of the car opposite the inward direction. This is, therefore,
a fictitious force. It is called the centrifugal force.
A second apparent force is called the Coriolis Force. This arises when one is in a
rotating frame of reference. Say that you are standing on the north pole and you
throw an object straight south at a high velocity. To you it will appear that the
object curves toward your right, in this case toward the west. The reason for this is
that in terms of meters per second, all latitudes to your south will be moving faster
than you in an easterly direction because in one day they must travel a farther
distance because they are further from the earth’s axis of rotation (remember that v
= ω r). If the object you threw is not in contact with the ground, it will have an
easterly component of velocity the same as it was when you threw it. The object,
then, will appear to curve to the right as it goes south.
If you are on the equator and throw an object toward the north, now it will have an
easterly component that is greater than the latitudes away from the equation, so the
object would appear to be curving now toward the east, which again is toward your
right.
In the northern hemisphere, things appear to turn toward your right do to the
Coriolis Force, and in the southern hemisphere, things appear to turn toward your
left. It is the Coriolis Force that explains the general wind circulation and oceanic
circulation pattern on the earth.
Steps to draw the general winds on Earth
• Sunlight is strongest nearer the equator.
• Air heated there rises and spreads out north and south.
• After cooling the air sinks back to the Earth's surface within the subtropical
climate zone between latitudes 25° and 40°.
• This cool descending air stabilizes the atmosphere, preventing much cloud
formation and rainfall. Consequently, many of the world's desert climates can be
found in the subtropical climate zone.
• Surface air from subtropical regions returns towards the equator to replace the
rising air, so completing the cycle of air circulation within the Hadley cell.