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Climate
What determines climate?
• Weather conditions change from day to day
• Climate describes the weather conditions in an area over a long period of time
• Climate is determined by temperature and precipitation
Temperature
• Areas that have similar average temperatures may have very different temperature ranges
• A temperature range includes all of the temperatures in an area, from the coldest temperature
extreme to the warmest temperature extreme.
• Temperature ranges provide more information about an area and are unique to the area
• Temperature ranges are a better indicator of climate than are temperature averages
Precipitation
• Precipitation is also an important part of climate.
• Average yearly precipitation alone is not the best way to describe a climate
• The pattern of precipitation in a region can determine the types of plants that grow there and
the length of the growing season
• Pattern of precipitation is a better indicator of the local climate than the average precipitation
alone
How is the sun’s energy related to Earth’s climate?
• The climate of an area is directly related to the amount of energy from the sun, or solar energy,
that the area receives
o This amount depends on the latitude of the area
o Latitude
o Different latitudes receive different amounts of solar energy
• The available solar energy powers the water cycle and winds, which affect the temperature,
precipitation, and other factors that determine the local climate
Latitude affects the amount of solar energy an area receives and that area’s climate
• Latitude helps determine the temperature of an area because latitude affects the amount of
solar energy an area receives
• Near the equator, the sun’s rays hit Earth directly
o At this angle, the solar energy is concentrated in a small area of Earth’s surface
o As a result, this area has high temperatures
• At the poles, the sun’s rays hit Earth at a lesser angle than they do at the equator
o At this angle, the same amount of solar energy is spread over a larger area
o Because the energy is less concentrated, the poles have lower temperatures
The sun powers the water cycle
• Precipitation
The sun powers wind
• The speed, direction, temperature and moisture content of winds affect the climate and
weather of the areas they move through.
How do Earth’s features affect climate?
• Winds have to flow around or over features on Earth’s surface, such as mountains
• The surface features of an area combine to form its topography
• Topography influences the wind patterns and the transfer of energy in an area
• Elevation refers to the height of an area above sea level
o Temperature changes as elevation changes
Topography can affect winds
• The broad, generally flat topography of the Great Plains gives rise to unique weather patterns
o Winds flow steadily over large distances before the merge
§ Produces thunderstorms and even tornadoes
•
When moist air hits a mountain, it is forced to rise up the side of the mountain
o The rising air cools and often releases rain
§ Supports plants
o The air that moves over the top of the mountain is dry
§ Air warms as it descends, creating a dry climate
Elevation influences temperature
• Elevation has a very strong effect on the temperature of an area
• The lower atmosphere is mainly warmed by Earth’s surface that is directly below it
• The warmed air lifts to higher elevations, where it expands and cools
• Even close to the equator temperatures at high elevations can be very cold
How do large bodies of water affect climate?
• Water absorbs and releases energy as heat more slowly than land does
• Water helps moderate the temperature of nearby land
• Sudden or extreme temperature changes rarely take place on land near large bodies of water
• Places that are inland but that are at the same latitude as a given place on a coast experience
wider ranges of temperatures
How do ocean currents affect climate?
• Ocean current is the movement of water in a certain direction
o Ocean currents move water and distribute energy and nutrients
• Surface currents are driven by winds and carry warm water away from the equator and carry
cool water away from the poles
• Currents moderate global temperatures
What are the three major climate zones?
• Each zone has a distinct temperature range that relates to its latitude
• Each of these zones has several types of climates
o These different climates result from differences in topography, winds, ocean currents,
and geography
Temperate
• Average temperature below 64 degrees Fahrenheit in the coldest month and an average
temperature above 50 degrees Fahrenheit in the warmest month
• Five temperate zone subclimates:
o Marine west coast, steppe, humid continental, humid subtropical, and Mediterranean
• Characterized by lower temperatures than the tropical zone
• Located between the tropical zone and the polar zone
Polar
• At latitudes 66.5 degrees and higher
• Coldest, temperatures rarely rise above 50 degrees Fahrenheit in the warmest month
• Three types:
o Subarctic, tundra, and polar ice cap
Tropical
• Average monthly temperature of at least 64 degrees Fahrenheit even during the coldest month
of the year
• Three subclimates:
o Rain forest, desert, and savanna