World Geography Chapter 3 Section 1 A. Introduction a. Weather b. Climate c. Both weather and climate are influenced by i. direct sunlight. ii. iii. iv. the features of the earth s surface. B. The Greenhouse Effect a. ; however, enough remains to warm the earth s land and water. b. The earth s atmosphere keeps heat from escaping back into space too quickly, creating a greenhouse effect, c. Without this greenhouse effect, the earth would be too cold for most living things. C. Earth s Tilt and Rotation a. The earth has an axis b. Because the Earth s axis is tilted at a, not all places on earth receive the same amount of direct sunlight. c. The earth s tilt affects the temperature Chapter 3 Page 1
d. The earth rotates, or spins,, making one complete rotation every 24 hours, and causing day and night. D. Earth s Revolution a. b. The earth s revolution, or, takes 1 year, or 365¼ days, which results in the changing of. i. March 21 and September 23 are called because the sun is directly over the equator and the days and nights are equal in length, marking the beginning of. ii. June 21 and December 22 are called because the sun is directly over the Tropic of Cancer or the Tropic of Capricorn, marking the beginning of. c. d. For six months one Pole is slanted toward the sun, receiving continuous sunlight, while the other Pole is slanted away from the sun, receiving no sunlight. Section 2 E. Introduction a. The climate of a location depends in part on latitude, elevation, wind and ocean currents, and landforms. F. Latitude a. i. The zones indicate how the sun s rays strike places within the zones. Chapter 3 Page 2
b. During the earth s yearly revolution around the sun, the sun s direct rays fall on the earth in a regular pattern. c. Low Latitudes i.. ii. The low latitudes receive direct rays of the sun year-round, and are often said to be in the tropics. d. Polar Areas i. When either the or the is tilted toward the sun, its polar area receives continuous sunlight. ii. Starting on about June 21, the sun never sets above a line called the Arctic Circle (66½ N). iii. In the Southern Hemisphere, the Antarctic Circle (66½ S) is a line that marks the boundary of. e. High and Middle Latitudes i. The latitudes between the North Pole and the Arctic Circle and between the South Pole and the Antarctic Circle are known as. ii. The high latitudes receive slanted rays of the sun throughout the year and have a generally. iii. The latitudes between the Tropic of Cancer and the Arctic Circle in the Northern Hemisphere and between the Tropic of Capricorn and the Antarctic Circle in the Southern Hemisphere are known as the iv. Many places in the middle latitudes have a temperate climate 1. The weather of most places in the middle latitudes changes dramatically with the seasons. Chapter 3 Page 3
G. Elevation a. b. The earth s atmosphere gets as altitude increases, so air temperatures with elevation. i. For every 1,000 feet gained, the temperature drops about 3.5 F. c. High mountains are generally cold places covered with ice and snow year-round, even though sunlight is very bright. H. Wind and Ocean Currents a. Wind and water combine with the effects of the sun to create the b. Wind and occurs when temperatures create differences in air pressure. c. Wind Patterns i. Prevailing winds are. ii. Trade winds are the prevailing winds in the, blowing toward the Equator from about 30 N latitude and 30 S latitude. iii. Westerlies are the prevailing winds in the belts between latitude and between latitude. iv. lie between 60 N latitude and the North Pole and between 60 S latitude and the South Pole. 1. Easterlies blow somewhat from east to west and push cold polar air toward the middle latitudes. v. The doldrums is a Chapter 3 Page 4
I. Ocean Currents a. Ocean currents,, generally move in the Northern Hemisphere and in the Southern Hemisphere. b. Currents are caused by... i. ii. iii. c. Ocean currents affect the climates of coastal lands that they flow along. d. Water and winds interact with temperature to cause precipitation J. Landforms a. The can also affect climates. b. Temperatures of land areas located near oceans do not change as much as c. Interior land areas experience much summers and much winters than land areas near the ocean. d. Temperatures, precipitation, and surface features interact with wind to affect climate. e. Winds that blow over an ocean and then meet a mountain range on the the side facing the direction from which the wind is blowing are pushed upward. f. The air that descends the other side of the mountains, the leeward side,. Section 3 K. Introduction a. Climate affects the soil and the plant life that grows in an area if people have not changed the natural environment. Chapter 3 Page 5
b. Geographers often divide the earth into five major climate regions: i. ii. iii. iv. v. L. Tropical Climates a. Tropical climate regions are found in or near the. b. The two kinds of tropical climate regions are and tropical savanna. c. Tropical Rain Forest Climate i. Tropical rain forest climate regions are throughout the year and are found near the. ii. Tropical rain forest vegetation grows thick in layers formed at different heights. 1. The in South America contains the world s largest tropical rain forest. 2. The same climate is found in other parts of South America, in the Caribbean area, and in parts of Africa and Asia. d. Tropical Savanna Climate i. Tropical savanna climate regions ii. Savannas are located farther from the Equator than tropical rain forest regions. iii. Savannas are characterized by temperatures, clumps of. M. Dry Climates a. Because of vegetation, dry climate regions are also divided into two types and. Chapter 3 Page 6
b. Desert Climate i.. ii. Scattered vegetation such as and can survive with little rain. iii. Underground springs, however, may support an oasis,. iv. Deserts can be. v. Desert climates cover about one-fifth of the earth s land surface. c. Steppe Climate i. Dry areas, often bordering deserts, are called steppes. ii. Steppe vegetation consists of. 1. The largest steppe stretches across eastern Europe and western and central Asia. N. Mid-latitude Climates a. The world has four mid-latitude climate regions: i. ii. iii. iv. b. Marine West Coast Climate i. Marine west coast climate regions are found along western coastlines between latitudes north and south. ii. Ocean winds produce summers and winters. iii. Rainfall is quite heavy in places, and it supports both. iv. Most deciduous trees. v. are those with both evergreen and deciduous trees. Chapter 3 Page 7
c. Mediterranean Climate i. Areas that have weather patterns and vegetation like those near the Mediterranean Sea are called Mediterranean climate regions. ii. These regions are generally found in coastal lands between latitudes north and south. iii. They have winters and summers. iv. Vegetation in Mediterranean climate regions is called chaparral, which includes. d. Humid Subtropical Climate i. Humid subtropical climate regions have a pattern of wind and high pressure related to nearby oceans, which causes. ii. Rain falls with, while winters are generally and. iii. Vegetation in humid subtropical climate regions includes, or prairie lands, and. iv. Forests consist of a mixture of broad-leaved evergreen trees, deciduous trees, and needle-leaved evergreens. e. Humid Continental Climate i. Humid continental climates are more influenced by, precipitation, or ocean temperatures. ii. The farther north in the humid continental climate regions, the winters and summers. O. High Latitude Climates a. There are three types of high latitude climates: i. subarctic ii. tundra Chapter 3 Page 8
iii. ice cap b. The subarctic climate regions lie. c. In some places only a thin layer of surface soil thaws. The frozen subsoil is known as. d. Subarctic Climate i. The subarctic s severe conditions plant life to mainly needle-leaved evergreen trees. 1. One vast subarctic forest stretches across northern Russia. ii. Geographers often use, the Russian word for this forest, to refer to subarctic climate regions in general. e. Tundra Climate i. The tundra climate regions ii. In summer the sun s slanted rays bring constant light but. iii. The tundra region s above the supports only certain low plants and plants that grow on rocks. f. Ice Cap Climate i. Because monthly temperatures average below freezing, ice cap climate regions support no vegetation, except a few species that can live on rocks. P. Highland Climates a. In mountain areas the climate varies with elevation. b. Near the bases of mountains,. c. Higher up are with small trees and shrubs. d. Above the, the elevation above which it is too cold for trees to grow, are scattered tundra plants. Chapter 3 Page 9
Q. Climatic Changes a. Climates change gradually over time. During the last 1 to 2 million years, for example,. b. Geographers have developed several possible explanations for what caused. c. One explanation is that variations in the sun s output of energy and in the earth s orbit may have caused our world to absorb less solar energy and cool off. d. Another hypothesis, or, suggests volcanic activity over long periods of time released massive amounts of dust into the atmosphere, which t. e. Geographers also believe that today cause changes in the world s climates. For example: f. Smoke from the burning of scatters the sun s rays. g. The burning of fossil fuels releases, preventing some surface heat from atmosphere. h. Gases produced by burning fuels mix with water in the air, forming. i. The exhaust from automobiles helps create smog,. j. Water projects, such as dams and river diversions, may cause new areas to become. R. El Niño a. El Niño is a recurring that has an important impact on global weather by setting off changes in the atmosphere. Chapter 3 Page 10
b. A weakening of trade winds that blow east to west, allowing a large mass of to move east toward, characterizes El Niño. c. El Niño used to occur every years but now happens more often. d. Scientists are not certain what causes El Niño, but many link it with global warming. e. Chapter 3 Page 11