Science 24.1

NORTH AMERICAN AIR MASSES

- CONTINENTAL tropical -desert of southwest U.S. -dry, HOT weather in SUMMER -do NOT form in WINTER - maritime TROPICAL -Atlantic - mild, CLOUDY weather in winter & hot, HUMID weather with THUNDERSTORMS in summer -Pacific - do NOT reach Pacific COAST - continental POLAR - COOL, dry weather in summer & very FOGGY weather in WINTER - MARITIME polar -Pacific - cool, FOGGY weather in summer & RAIN and snow in winter -Atlantic - COOL weather, LOW clouds, and FOG in summer & cold, CLOUDY weather and SNOW in winter

HOW AIR MOVES

- air moves from HIGH pressure to LOW pressure regions -high pressure = COLD air SINKS (POLES) -low pressure = WARM air RISES (EQUATOR) - air mvoes from POLES twoard EQUATOR -influenced by the CORIOLIS effect

AIR MASSES

- small PRESSURE differences means air remains STATIONARY or moves very SLOWLY -allows the air to take on the TEMPERATURE and HUMIDITY of the region forming an AIR MASS - air mass - LARGE body of air with the same TEMPERATURE and MASTURE content -polar (P) - COLD -TROPICAL (T) warm -MARITIME (m) MOIST; form over OCEAN -continental (c) - DRY; form over LAND - ex. CONTINENTAL polar (cP) - cold, DRY air - ex. maritime TROPICAL (mT) - WARM, moist air

WHAT IS WEATHER

- state of the ATMOSPHERE at a given PLACE and TIME - includes the amount and tyupe of CLOUDS, rain, SNOW, lightning, WIND speed, PRESSURE, and TEMPERATURE

How are air masses classified?

Air masses are classified by their source regions.

Identify the location where a cold, dry air mass would form.

Air masses that form over frozen polar regions are very cold and dry.

Identfiy the location where a warm, moist air mass would form.

Air masses that form over tropical oceans are warm and moist.

List the four main types of air masses (HINT: Think about the possible combinations)

Continental Air Masses, Maritime Air Masses, Tropical Air Masses and Polar Air Masses.

What weather conditons do continental air masses generally bring when they move into a region?

Continental air masses bring dry weather conditions when they move into another region.

continental

Dry air / symbol: c / form over land

What are the characteristics of air masses tha form over plar areas?

It is cold air air masses.

What happens to air when the air pressure differences are small?

The remains relatively stationary

What weather conditions do maritime air masses generally bring when they travel to a new location?

They bring precipitation and fog.

How do air masses that form over the ocean differ from continental air masses?

They differ by the humidty in their air masses.

What are the characteristics of air masses that form over polar areas?

Warm air masses.

How would temperature and humidity at a given location change when a maritime tropical air mass is replaced by a continental polar air mass?

When a maritime tropical air mass is replaced by a continental polar air mass, the temperature and humidity would change at a given location by each decreasing because continental polar air masses bring dry, cold weather.

How does an air mass form?

When air pressure differences are small, air remains relatively stationary. if the air remains stationary or moves slowly over a uniform region, the air takes on the characteristic temperature and humidity of that region. A large body of air throughout which temperature and moisture are similar is called an AIR MASS. Air masses that form over frozen polar regions are very cold and dry. Air masses that form over tropical oceans are warm and most.

air mass

a large body of air throughout which temperature and moisture content are similar

polar

cold air / symbol: p / polar areas

The region around the

equator

Air moves from

high (pressure)

to

low (pressure).

maritime

moist air / symbol: m /

then the regions at the

poles (do).

receives more

solar (energy)

tropical

warm air / symbol: t / form tropical area