Ch.18 Geology 1401
How are wind measurements described?
according to direction and speed
What substance creates atmospheric pressure?
air molecules
Aneroid Barometer
calculate elevation for use in making maps.
In the evening, the weather forecaster on the radio says that the barometer is rising. What should you be prepared for as you get ready to go to school in the morning?
clear, sunny skies
Toward which direction would a northwest wind blow?
southeast
Which way does air move in an anticyclone in the Northern Hemisphere?
down, and in a clockwise direction
Due to the Coriolis and pressure-gradient forces, winds in a low-pressure system in the Northern Hemisphere blow in which direction?
inward and counterclockwise
On a weather map, you notice a large pressure system centered over the Pacific Northwest. This system shows isobars that increase toward the center. In which direction would you expect the winds to be blowing in this system?
outward and clockwise
What would global wind circulation look like on a nonrotating Earth?
-Cold air from the poles would move toward the equator near Earth's surface. -Warm air from the equator would move toward the poles in the upper atmosphere.
Why are anticyclones not generally associated with clouds and rain?
Air in anticyclones undergoes warming as the air descends.
Why are cyclones generally associated with clouds and rain?
Air in cyclones undergoes cooling as it rises.
At which location would you expect air to have the highest density on a typical winter day? Laredo, Texas Edmonton, Alberta Phoenix, Arizona Barrow, Alaska Denver, Colorado
Barrow, Alaska
Description of cyclonic and anticylonic winds in the Northern and Southern Hemispheres?
Cyclonic winds are counterclockwise in the Northern Hemisphere.
What is an anticylone?
a center of high atmospheric pressure
What is a cyclone?
a center of low atmospheric pressure
What is the Coriolis effect?
a deviation in wind direction caused by Earth's rotation
On a weather map, you examine the isobars and find that concentric rings of the pressure system increase in air pressure toward the center. Which type of pressure system is depicted on the map?
anticyclone
What instrument is used to measure air pressure?
barometer
At what latitudes do the trade winds occur?
between the equator and 30 degrees N and S
The most precise instrument for measuring wind speed is a ________.
cup anemometer
What wind patterns and weather conditions are associated with low-pressure systems?
cyclonic winds and stormy weather
Which way does air move in an anticyclone in the Southern Hemisphere?
down, and in a counterclockwise direction
You are watching the evening news and the weather segment begins. The meteorologist comments that the pressure tendency is rising. Which of the following set of weather conditions would match this pressure tendency?
extensive clouds with moderate winds and steady rain
Because of divergence of air associated with an anticyclone, what type of weather is generally associated with this pressure system?
fair and clear
Which parameter has the most influence in changing air pressure?
horizontal movement of air
Which way does air converge on a cyclone in the Northern Hemisphere?
in a counterclockwise direction
How does air move near the top of a cyclone?
in the same direction as air in the upper atmosphere
What force is responsible for generating wind?
pressure gradient
Looking at a weather map of North America, you notice that the isobars in an approaching pressure system are very closely spaced and show a decrease in pressure toward the center. What type of weather would you anticipate over the next 24 to 48 hours?
rainy and windy
Which pressure system is linked to the Sahara Desert?
subtropical high
What conditions would dominate in the southeastern United States in an El Niño year?
wetter and cooler than normal
