Chapter 2, Section 1

I. Climates and Ecosystems

A. Weather and Climatei. Weather

a. The condition of the bottom layer of the earth’s atmosphere in one place over a short period of time.

b. Descriptions usually mention temperature, moisture or precipitation, and wind.

1. ex. “Warm, Dry and Calm” or “cold, snowy and windy.”

ii. Climatea. The term for the weather patterns that an area typically experiences over a long period of time. b. The climate of an area depends on

elevation, latitude, and location in relation to nearby landforms and bodies of water.

“Climate is what you expect, weather is what you get. “

B. The Sun and the Earthi. The Sun, is the source of the earth’s climates

and life on earth.ii. The Greenhouse Effect

a. Traps the suns radiation to keep earth warm.

iii. Rotation and Revolutiona. Rotation

1. Earth’s movement on its axis. b. Revolution

1. Earth orbits the sun. 2. One complete orbit every year is a revolution.

Rotation

Left Side: Light from Sun = daytime

Right Side:Dark/No Sun = Nighttime

Earth is constantly rotating on its axis.

Revolution

While rotating on its own axis, the earth is also orbiting the sun.

3. Earth’s tilt means sunlight strikes different parts of the planet more directly at certain times of the year.

When North Pole is tilted towards sun, the sun’s rays fall more directly on the Northern Hemisphere, bringing longer, warmer days. = AKA Summer in the Northern Hemisphere and Winter in the Southern Hemisphere. Changes in season marked by summer and winter solstices.

C. Distributing the Sun’s Heati. Heat from suns rays does not stay in place.

a. Convection helps distribute heat in air and water.b. Movements of air are called winds.c. Movements of water are called currents.

ii. Winda. Pattern of winds begins when light, warm air

rises from the Equator and flows northward and southward toward the poles.

b. Air from cool regions move toward equator.

D. Precipitationi. Humidity – amount of water vapor contained

in the atmosphere. ii. Warm, less-dense air absorbs more moisture

than cool air. When this air cools, it cannot contain all of its water vapor. Forms liquid.

iii. Geographers divide precipitation into three types:

a. Convectional Precipitation b. Orographic Precipitation c. Frontal Precipitation

a. Convectional Precipitation 1. Occurs when hot, humid air rises from the

earth’s surface and cools, thereby losing its ability to hold much water.

2. Common near equator and tropical areas, where hot, humid surface air exists.

b. Orographic Precipitation1. Occurs when warm, moist air is forced upward

when passing over high landforms, causing precipitation.

2. Common on seacoasts where moist, ocean winds blow toward coastal mountains.

3. Warm winds cool as they rise up mountains, clouds form, precipitation occurs, wind is cool and dry by the time it reaches the other side of the mountain.

4. This dry, hot air often creates dry climates behind coastal mountains. Ex. California’s Mohave Desert lies inland behind the Sierra Nevada.

c. Frontal Precipitation1. Occurs when two fronts (air masses) of

different temperatures meet. 2. Warm air is forced upward by the heavier,

cool air.3. Rising warm air cools, and frontal

precipitation occurs.

E. Other Influences on Climatei. Temperature and Precipitation are the major

influences on climate. ii. Other influences include:

a. Nearby Bodies of Waterb. Elevationc. Nearby Landforms

a. Nearby Bodies of Water1. Water temperature changes slowly compared

to land. 2. Ocean surface temperature varies only 10

degrees throughout the year. 3. Winds that blow over large bodies of water

take on the water’s temperature. Winds moderate land temps as they blow on shore.

ex. Marine Climates

Always seems to rain in ________?

b. Elevation

1. Mount Kilimanjaro is located on the Equator in Tanzania, Africa.

2. However, it is capped by snow year-round. 3. The mountains elevation is 19,341 feet above

sea level. This affects its climate much more than does its location in the tropics.

c. Nearby Landforms