Atmosphere & Climate ChangeChapter 13, Section 1: Climate & Climate ChangeStandards: SCSh2a,b, 3c, 4a, 6a, d

What is the difference between weather & climate? Weather is the state of the

atmosphere at a particular place at a particular moment. Ex: it is raining outside

today. Climate is the long-term

prevailing weather conditions at a particular place based upon records taken. Ex: it is hot and humid in

the southeast during the summer months.

What factors determine climate? Latitude Atmospheric

circulation patterns Oceanic circulation

patterns Local geography Miscellaneous

Solar activity Volcanic activity

Latitude Distance from the equator measured

in degrees north or south. Low latitudes: near the equator (0°)

and about 30° above and below. Gets most sunlight, night & day are

about 12 hrs each, temperatures are high year round and no summers or winters

High latitude: from about 30° latitude to the north & south pole (90°). Gets less sunlight, night & day vary

during summer & winter, Summer- 12 hrs daylight in our area;

2-4 hrs of nighttime at poles Winter- 8 hrs daylight in our area; 24

hrs; 2-4 hrs of daylight at poles.

Atmospheric Circulation 3 important properties of air:

Cold air sinks, compresses, and warms b/c it is denser than hot air.

Warm air rises, expands, and cools as it rises.

Warm air can hold more water vapor than cold air. As warm air cools it condenses

and makes rain The rotation of these 3

properties creates wind. Uneven heating of Earth & Earth

spinning alter the movement of wind on Earth and create wind patterns.

Atmospheric CirculationGlobal Circulation Patterns At equator, cool air cannot sink

due to all the warm air rising up. This cool air is forced away from

the equator & moves toward the poles.

At about 30° N and S of equator, the cool sinks

The cool air starts to warm and sucks moisture from ground below.

This is what creates deserts at 30° N & S latitude.

Same basic process happens at 60° latitude.

Atmospheric CirculationPrevailing Winds Winds blow predominantly in one

direction throughout the year. Because Earth rotates, these

winds do not blow directly north or south- instead they are deflected

Wind patterns in Northern Hemisphere: Tradewinds- btwn 0-30° latitude;

blow from the NE Westerlies- btwn 30-60° latitude;

blow from the SW Easterlies- btwn 60°-poles; blow

from the NE parts of poles

Air circulation pattern animation

Ocean circulation patterns Have large effect on

climate because water holds lots of heat.

Movement of ocean water caused by Winds Earth’s rotation

Moving ocean water redistributes warm and cold surface water

Can have an effect on local coastal climates.

El Nino Southern Oscillation (ENSO)

El Nino Change in warm & cold

water masses in Pacific ocean

Pacific winds strengthen and push warm air & rain toward southern US & South America. Makes it drier in Australia & Indonesia

La Nina Opposite of El Nino… water

is cooler than normal. Both can alter fishing

industry in S. America. El Niño-Southern Oscillation - YouTube

Topography Height above sea level

influences climate. Temperatures fall 11°F for

every ½ mile increase in elevation.

Rain shadow effect As air moves east toward

Rocky mtns, the height of the Rockies block the weather. Rain falls on the western side of the mountain making the eastern side drier.

Miscellaneous Influences Solar Activity

Solar maximum- sun emits an increased amount of UV radiation, warming the surface of the earth a little

Volcanic Activity Produce sulfur dioxide

that can react with dust & water vapor to make haze that reflects light and cools global temperatures

What causes our seasonal changes? Caused by tilt of

Earth’s axis. Angle at which the

sun’s rays strike the Earth changes as the Earth moves around the sun.

You should be able to: Explain the difference between weather

and climate. Name four factors that determine

climate. Explain why different parts of the Earth

have different climates Explain what causes the seasons.