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chapter 21
air masses
Question | Answer |
---|---|
What are differences in air pressure caused by? | unequal heating of Earth's Surface |
What receives more solar energy, the region by the equator or the region by the poles? | the region along the equator |
The heated equatorial air rises and creates what? | a low pressure center |
Cold air near the poles sink and this creates what? | high pressure centers |
What creates wind patterns? | Differences in air pressure at different locations on Earth |
How does air move? | from areas of high pressure to areas of low pressure |
If air moves from high pressure to low pressure how does air move (use equator and poles in the answer) | in general, surface air moves from the poles the the equator |
why does air move from the poles to the equator | air moves from high pressure (poles) to low pressure (equator) |
When does surface air not move from high pressure to low pressure | at high altitudes the warm air from the equator to the poles |
Temperature and pressure differences on Earth's surface creates what? | three wind belts in the Northern Hemisphere and three wind belts in the Southern Hemisphere |
What are wind belts influenced (or affected) by? | Coriolis effect |
What is the Coriolis effect | an effect whereby a mass moving in a rotating system experiences a force (the Coriolis force ) acting perpendicular to the direction of motion and to the axis of rotation. |
When does the Coriolis effect occur? | when winds are deflected by Earth's rotation |
The processes that affect air movement also influence what? | storms |
When air pressure differences are small the air remains relatively __________ | stationary |
If the air moves slowly over a uniform region, it takes on the characteristic _______ and ______ of that region | temperature and humidity |
A What is the definition of air mass? | a large body of air throughout which temperature and moisture content are similar |
Describe air masses that form over frozen polar regions | very cold and dry |
Describe air masses that form over tropical oceans | they are warm and moist |
The motion of Earth's atmosphere can lead to the formation of what | powerful storms such as Hurricane Katrina |
How are air masses classified? | according to their source regions |
The source regions determine the ______ and ______ of the air masses | temperature and humidity |
The source regions for cold air masses are ____ areas | polar areas |
The source region for warm air masses are _____ areas | tropical areas |
Air masses that form over land are called what | continental |
Air masses that form over oceans are called what | maritime |
Continental air masses are _____ | dry |
Maritime air masses are ______ | moist |
Tropical air masses are _______ | warm |
Polar air masses are | cold |
What is the symbol used to mean continental air mass | c |
What is the symbol used to mean Maritime air masses | m |
What is the symbol used to mean tropical air masses | T (capital T) |
What is the symbol used to mean Polar air masses | P (capital P) |
Continental air masses form over large ________ | landmasses |
give 3 examples of where a continental air mass might form | 1. northern Canada 2. northern Asia 3. southwestern United States |
Because continental air masses form over land the level of humidity is ______ | very low |
An air mass may remain over its source for how long? | for days or weeks |
Air masses will eventually move into other regions because of what? | global wind patterns |
In general continental air masses bring what kind of weather conditions when they move into another region | dry weather conditions |
There are two types of continental air masses. What are they | 1. continental polar (cP) 2. continental tropical (cT) |
Continental polar air masses are what | cold and dry |
Continental tropical air masses are what | warm and dry |
Where do maritime air masses form | over oceans and other large bodies of water |
maritime air masses take on the characteristics of what? | the water over which they form |
The humidity in maritime air masses are ______ then the humidity in continental air masses | higher |
When maritime air masses (which are high humidity) travel to a new location they bring what type of weather? | precipitation and fog |
What are the two types of maritime air masses? | 1. maritime polar (mP) 2. maritime tropical (mT) |
Maritime polar air masses are what? | moist and cold |
maritime tropical air masses are what? | moist and warm |
The four types of air masses that affect the weather of North America come from what 6 locations? | 1. Continental polar Canadian 2. Continental tropical 3. Maritime polar Pacific 4. Maritime polar Atlantic 5. Maritime tropical Pacific 6. Maritime tropical Atlantic |
cP (continental polar) air mass comes from what source location | polar regions in Canada |
the cP air mass moves in which direction | south-southeast |
the cP air mass brings what type of weather | cold and dry |
the mP (maritime Polar) air mass comes from what source locations? | polar Pacific and polar Atlantic |
the mP air mass moves in what directions | southeast; southwest-south |
the cT (continental tropical) air masses come from what source locations | U.S. southwest |
the cT (continental tropical) air masses move in what direction | north-northeast |
What weather does the cT air masses bring | warm and dry |
the mT (maritime tropical) air masses come from what source locations | tropical Pacific and tropical atlantic |
What direction do the mT air masses move | northeast; north-northwest |
What type of weather does the mT air masses bring | warm and moist |
Continental tropical air masses form over the ______ of the southwestern United States | deserts |
the continental tropical air masses bring what type of weather in the summer | dry hot weather |
true or false The continental tropical air masses do not form in the winter | true |
Maritime tropical air masses form over what three bodies of water? | 1. warm water of the tropical Atlantic ocean 2. Caribbean Sea 3. Gulf of Mexico |
The Maritime tropical air masses bring what type of weather to the Eastern United states in the winter | mild, cloudy weather |
In the summer Maritime tropical air masses bring what type of weather | hot humid weather and thunderstorms |
Maritime tropical air masses do not usually reach what coast | pacific coast |
In the winter maritime tropical air masses bring what weather to the coast and southwestern deserts? | moderate precipitation |
Polar air masses from what three regions influence weather in North America | 1. northern Canada 2. northern Atlantic Ocean 3. northern Pacific ocean |
Continental polar air masses form over what type of land | ice and snow-covered land |
continental polar air masses move into Northern United states and can occasionally reach as far south as the ____________________ | Gulf Coast of the United States |
In the summer continental polar air masses bring what type of weather | cool dry weather |
In the winter the continental polar air masses bring what type of weather | very cold weather to the northern united states |
Where do Maritime polar air masses form | over the North Pacific Ocean |
Describe the weather the Maritime polar air masses bring | summer - very moist cool foggy weather winter - bring rain and snow to the pacific coast |
Maritime polar Atlantic air masses usually move _______ toward ________ | Eastward; Europe (sometimes they can move west toward U.S. East coast |
when Maritime polar Atlantic occasionally moves toward the west, what type of weather does it bring? | winter - cold, cloudy and snow Summer - cool weather, low clouds, and fog |