World Geography TodayChapter 3 Weather and Climate Preview Section 1: Factors Affecting ClimateFactors Affecting Climate Section 2: Weather FactorsWeather Factors Section 3: Climate and Vegetation PatternsClimate and Vegetation Patterns Chapter Wrap-Up

World Geography TodayChapter 3 Read to Discover How does the Sun affect Earth’s atmosphere? How does atmospheric pressure distribute energy around the globe? How do global wind belts affect weather and climate? How do the oceans affect weather and climate? Section 1: Factors Affecting Climate

World Geography TodayChapter 3 Question By which processes does the Sun interact with Earth’s atmosphere? Section 1: Factors Affecting Climate

World Geography TodayChapter 3 The Sun’s Effect on Earth The Sun’s energy reaches Earth. Half of the energy is reflected back into space or absorbed by the atmosphere. The other half is absorbed by Earth’s surface and converted into heat energy. The atmosphere traps this heat in a process called the greenhouse effect. Section 1: Factors Affecting Climate The greenhouse effect helps keep the planet warm.

World Geography TodayChapter 3 Low-pressure zones are caused by warm air, which expands and rises. High-pressure zones are caused by cold air, which is dense and sinks. Pressure differences cause airflow and energy distribution around the globe. Warm air moves through the upper atmosphere until the air cools and falls; cold air sinks toward Earth’s surface and then heats up and rises. Section 1: Factors Affecting Climate Atmospheric Pressure

World Geography TodayChapter 3 Pressure differences cause wind. Winds move heat and cold across Earth’s surface. Prevailing winds blow from the same direction most of the time, causing similar weather. A front occurs when two air masses of widely different temperatures or moisture levels meet. Section 1: Factors Affecting Climate Global Winds

World Geography TodayChapter 3 Water heats and cools more slowly than land, making coastal areas milder than inland areas. Ocean currents move heat between the tropics and polar regions, helping to maintain Earth’s energy balance. Section 1: Factors Affecting Climate Oceans

World Geography TodayChapter 3 Read to Discover What are the common forms of precipitation, and how are they formed? How do mountains and elevation affect weather and climate? What are the different types of storms, and how do they form? Section 2: Weather Factors

World Geography TodayChapter 3 Question What are the steps in the formation of precipitation, and what are the four common types of precipitation? Section 2: Weather Factors

World Geography TodayChapter 3 Formation of Precipitation RainSnowSleetHail Condensation clouds, dew, fog, frost EvaporationHumidity Section 2: Weather Factors

World Geography TodayChapter 3 Rain—Liquid formed through condensation of water vapor Snow—Ice crystals formed in clouds Sleet—Rain that freezes as it falls Hail—Chunks of ice formed in storm clouds Section 2: Weather Factors Forms of Precipitation

World Geography TodayChapter 3 Question How do mountains and elevation affect weather and climate? Section 2: Weather Factors

World Geography TodayChapter 3 Increase in elevation causes drop in temperature. Mountains cause orographic effect: Moist air meets a barrier and is pushed upward, causing cooling, condensation, and precipitation. Mountainside facing wind is the windward, wetter side; side facing away from wind is the leeward, drier side, called the rain shadow. Section 2: Weather Factors

World Geography TodayChapter 3 Middle-latitude storms form when cold, dry polar air mixes with moist, warm tropical air. Examples include thunderstorms and tornadoes. Tropical storms are usually smaller and lack fronts. Examples include hurricanes and typhoons. Section 2: Weather Factors Types of Storms

World Geography TodayChapter 3 Read to Discover How do the two tropical climates differ? What conditions are common in dry climates? What climates are found in the middle latitudes? What characterizes high-latitude and highland climates? Section 3: Climate and Vegetation Patterns

World Geography TodayChapter 3 Question What are the characteristics of tropical humid and tropical wet and dry climates? Section 3: Climate and Vegetation Patterns

World Geography TodayChapter 3 Tropical Humid Climate Close to equator Warm temperatures Rainfall all year Receives Sun’s rays directly all year Rising warm air Rain forests Monsoons Tropical Wet and Dry Climates North and south of tropical humid Caused by seasonal change in this area Alternating wet and dry seasons Savannas Section 3: Climate and Vegetation Patterns

World Geography TodayChapter 3 Generally centered about 30 degrees north and south of equator Subtropical high-pressure zone causes sinking dry air, with little rain. Winters may be very cold, summers very hot. Hardy plants and animals Section 3: Climate and Vegetation Patterns Dry Climate Areas

World Geography TodayChapter 3 Mediterranean—Long, dry summers and mild winters; scrub woodland vegetation Humid Subtropical—Hot, humid summers and mild winters; temperate forests Marine West Coast—Mild all year; may support dense forests Humid Continental—Variable, with four seasons; enough rain to support forests Section 3: Climate and Vegetation Patterns Middle-Latitude Climates

World Geography TodayChapter 3 Subarctic—Long, cold winters and short, warm summers; vast evergreen forests Tundra—Long winters, with permafrost; low shrubs, lichens, mosses, ferns Ice Cap—Polar climates; few land plants or animals Highland—Varies by elevation, with low elevations relatively mild and high elevations similar to ice cap Section 3: Climate and Vegetation Patterns High-Latitude and Highland Climates

World Geography TodayChapter 3 Chapter Wrap-Up Understanding the Main Ideas 1.How does latitude relate to climate? 2.How do atmospheric pressure zones and ocean currents affect Earth’s energy balance? 3.On a global scale, where is precipitation most common? 4.What effects can hurricanes have on local environments? 5.Where will you find climates that are generally warm and wet all year? What creates dry weather conditions in arid regions?