GL 107 Earth Systems Science

K. Hannula

Discussion questions for 11/28/07

1.  Why doesn't it rain (or snow) whenever it is cloudy?

In order for rain (or snow) to reach the ground, water needs to collect in much larger drops than are present in cloud droplets.  Otherwise, the water will evaporate before it hits the ground.

2.  What is the Coriolis effect?  What direction does it make winds curve in the Northern Hemisphere?

The Coriolis effect is the deflection of moving objects (including winds and ocean currents) due to the earth's rotation.

Winds in the northern hemisphere curve right due to the Coriolis effect.  (In the southern hemisphere, winds curve left.)

3.  Describe the global pattern of winds.  What direction do winds blow between the equator and 30 degrees north and south?  What direction do winds blow in the mid-latitudes (30 to 60 degrees north and south)?  What direction do winds blow near the poles?

Near the poles: winds blow from east to west (polar easterlies).

Mid-latitudes (30 to 60 degrees north and south): winds blow from west to east (prevailing westerlies).

Tropics (equator to 30 degrees north and south): in the northern hemisphere, winds blow from the northeast (northeast trade winds); in the southern hemisphere, winds blow from the southeast (southeast trade winds).