Ch. 3 Weather and Climate

http://www.youtube.com/watch?v=lrPS2HiYVp8

Section 1 Factors Affecting ClimateI. The Sun and Latitude

A. Weather is the condition of the atmosphere at a given time and place

B. Climate-weather conditions in a region over a long period of time

C. The closer you are to the tropics and the sun’s direct rays, the warmer you are…duh

D. Temperature-measurement of heat

E. Atmosphere reflects half of sun’s energy and absorbs the other half which heats up the earth

F. Greenhouse Effect-Earth allows sun’s heat in, traps it and slowly allows it to release into space

G. Global Warming-CO2 absorbs heat

H. Some say man is responsible while others say it’s a natural cycle

Do you know?

• How does the Earth’s Atmosphere help keep the planet Warm?

• Green house effect- slowing the loss of heat into space

Random Fact • Venus and global warming

– Venus is 96 % CO2 and because of this it is 890 F

• The Little Ice age 1500’s -1800’s

II. Atmospheric Pressure

A. Pressure of air

B. Higher you go, less pressure

C. As air heats up, it expands, becomes less dense and rises (low pressure system)

D. Air rises, cools and forms water vapor

E. Centers of low pressure systems are called cyclones… sometimes a slight breeze while other times a powerful storm

F. High pressure systems are created from cold air sinking towards the Earth

G. Usually bring stable, clear and dry weather

Do you Know

• What kind of weather is usually associated with an area of Low pressure?

• Unstable weather, anything from a slight breeze to bad storms

H. Look at pressure diagram on Page 43.III. Global Wind Belts A. Wind flows from high pressure areas to low

pressure areas B. Tire C. Prevailing winds-blow from the same

direction all the time…NE and SE trade winds, westerlies, easterlies

D. Doldrums-along Equator, calm…little wind

E. Front-two air masses of widely different temperatures or moisture levels meet

F. Usually results in precipitation

G. Prevailing winds up in atmosphere make up the jet stream… wind speed can reach 300 miles per hour

H. Jet streams move heat and major weather patterns

Do you Know?

• How is wind directly related to the differences of air pressure?

• Wind flows from high areas of high pressure to low pressure areas

IV. Ocean and Currents

A. Water heats and cools more slowly than land

B. Locations near large bodies of water have more consistent temps then inland locations

C. Earth’s wind, rotation and temperatures create currents (great rivers of sea water)

D. Move clockwise in NH and counter in SH

E. Currents help balance water temperatures in the oceans by moving it all around.

Do you know?

• What are the main forces that create ocean currents?

• Wind, earth’s rotation, varying ocean temperatures

Read to Discover • What are the common forms of

precipitation, and how are they formed?• How do mountains and elevation affect

weather and climate?• What are the different types of storms, and

how do they form?

Section 2: Weather Factors

Formation of Precipitation

Rain Snow Sleet Hail

Condensationclouds, dew, fog, frostEvaporation Humidity

Section 2: Weather Factors

• Rain—Liquid formed through condensation of water vapor

• Snow—Ice crystals formed in clouds• Sleet—Rain that freezes as it falls• Hail—Chunks of ice formed in storm clouds

Section 2: Weather FactorsForms of Precipitation

• Increase in elevation causes drop in temperature.

• Mountains cause orographic effect: Moist air meets a barrier and is pushed upward, causing cooling, condensation, and precipitation.

• Mountainside facing wind is the windward, wetter side; side facing away from wind is the leeward, drier side, called the rain shadow.

Section 2: Weather Factors

• Middle-latitude storms form when cold, dry polar air mixes with moist, warm tropical air. Examples include thunderstorms and tornadoes.

• Tropical storms are usually smaller and lack fronts. Examples include hurricanes and typhoons.

Section 2: Weather Factors

Types of Storms

Read to Discover• How do the two tropical climates differ?• What conditions are common in dry

climates?• What climates are found in the middle

latitudes?• What characterizes high-latitude and

highland climates?

Section 3: Climate and Vegetation Patterns

Tropical Humid Climate

• Close to equator• Warm temperatures• Rainfall all year• Receives Sun’s rays

directly all year• Rising warm air• Rain forests• Monsoons

Tropical Wet and Dry Climates

• North and south of tropical humid

• Caused by seasonal change in this area

• Alternating wet and dry seasons

• Savannas

Section 3: Climate and Vegetation Patterns

• Generally centered about 30 degrees north and south of equator

• Subtropical high-pressure zone causes sinking dry air, with little rain.

• Winters may be very cold, summers very hot.

• Hardy plants and animals

Section 3: Climate and Vegetation Patterns

Dry Climate Areas

• Mediterranean—Long, dry summers and mild winters; scrub woodland vegetation

• Humid Subtropical—Hot, humid summers and mild winters; temperate forests

• Marine West Coast—Mild all year; may support dense forests

• Humid Continental—Variable, with four seasons; enough rain to support forests

Section 3: Climate and Vegetation Patterns

Middle-Latitude Climates

• Subarctic—Long, cold winters and short, warm summers; vast evergreen forests

• Tundra—Long winters, with permafrost; low shrubs, lichens, mosses, ferns

• Ice Cap—Polar climates; few land plants or animals

• Highland—Varies by elevation, with low elevations relatively mild and high elevations similar to ice cap

Section 3: Climate and Vegetation Patterns

High-Latitude and Highland Climates