WEATHER AND CLIMATE2-1

I. Weather and Climate• A. Weather – condition of the bottom layer of the

earth’s atmosphere in one place over a short period of time

• B. The weather in one place might be affected by the weather in another area far away

• C. Climate – weather patterns that an area typically experiences over a long period of time

• D. Climate depends on a number of factors• 1. elevation• 2. latitude• 3. location in relation to nearby landforms (ex.

mountains)• 4. location in relation to nearby bodies of water (ex.

oceans)

• E. Climates may change, but it occurs over a very long period of time unlike weather

II. The Sun and the Earth• A. The Sun – an intensely hot star that gives off

energy and light that are essential for plant and animal survival

• B. The sun is 93 million miles away from the Earth

• C. Greenhouse Effect• 1. only a small amount of radiation reaches the earth’s atmosphere• 2. what is left is enough to warm the earth’s land and water• 3. the atmosphere helps prevent heat from escaping back into space too quickly• 4. without the Greenhouse Effect, the earth would be too cold to sustain most living things

• D. Rotation and Revolution• 1. rotation – the spinning motion of the earth, like a top

on its axis, as it travels through space• 2. axis – invisible line through the center of the earth

from pole to pole• 3. the earth completes 1 rotation in approximately 24

hours• 4. whatever side is facing the sun, it is in daytime• 5. whatever side is facing away from the sun, it is in

nighttime• 6. since the earth turns from west to east, the sun rises in

the EAST and sets in the WEST

• 7. revolution – one complete orbit around the sun• 8. the earth completes one revolution every 365 ¼ days• 9. to account for the quarter day, every four years we have an extra day called Leap Day in February• 10. The earth’s tilt on its axis determines which part of the planet the sunlight strikes more directly…thus creating seasons• a. Season changes in the summer and winter

are called solstices• b. Season changes in the spring and fall are

called equinoxes

• E. Latitude and Climate• 1. the sun’s rays always fall directly at or near the Equator• 2. this is why the closer you are to the Equator, the warmer the climate, while the farther you are from the Equator (poles), the colder the climate• 3. geographers use latitude to divide the world into climate zones• a. Tropical zones• b. Temperate zones• c. Polar zones

III. Distributing the Sun’s Heat• A. Heat from the sun is distributed by a process

called convection (transfer of heat from one place to another)

• B. Air (Wind)• 1. light, warm air rises from the Equator and flows north and south towards the poles

• C. Water (Currents)• 1. warm water from the Equator flows towards the poles

IV. Precipitation• A. Precipitation – all forms of water that fall from

the atmosphere onto the earth’s surface• B. Warm air absorbs moisture, but when it cools

down, it cannot hold the water vapor…thus it must release it

• C. Different types of precipitation:• 1. snow• 2. rain• 3. sleet• 4. hail

What type of precipitation falls depends on air temperature and wind conditions

V. Other Influences on Climate• A. Nearby Bodies of Water• B. Elevation• 1. air temperature decreases as you get higher in elevation• 2. Mt. Kilimanjaro is located almost on the Equator, however, it has snow on the peak all year long

• C. Nearby Landforms• 1. The following also have an affect on climate:• Coastal mountains• Inland mountains• Large desert areas• Lakes• Forests• Tall buildings that are closely concentrated• Pavement and concrete in large quantities

VI. World Climate Regions

• A. 5 broad types of climate regions• 1. tropical• 2. dry• 3. moderate• 4. continental• 5. polar

VII. Changing Climates• A. Many climate changes in the past have

occurred because of nature• B. More changes are now occurring because of

human action• *global warming