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Global Climate Concepts 26 October 2016 Agenda • • • • Journal: FRQ Answer FRQ Notes: Climate Concepts IP: Ocean & Air Current Maps Objectives • Explain how unequal heating of the earth influences global climate. • Diagram global air and ocean currents. • Identify the major layers of the atmosphere. • Describe how Earth’s tilt affects seasonal differences in temperature. The Unequal Heating of the Earth • For this section: – Identify the five layers of the atmosphere – Discuss the factors that cause unequal heating of the Earth – Describe how the Earth’s tilt affects seasonal differences in temperatures Earth’s atmosphere is composed of layers Atmospheric layers • Layers get less dense as you get further from earth • Troposphere – Closest to Earth’s surface • Stratosphere – Above the troposphere – Contains ozone layer • Mesosphere • Thermosphere • Exosphere Solar Energy Reaching Earth Varies • First cause of unequal warming of the earth is variation in the angle at which the Sun’s rays strike the earth. • Sun’s rays hit the atmosphere at the equator at a perpendicular angle, whereas in the poles the Sun’s rays hit the atmosphere at an oblique angle. • Sun’s rays must travel a further distance to hit the earth at the poles. Solar Energy Reaching the Earth Varies Solar Energy Reaching the Earth Varies • Second cause of uneven warming is variation in the amount of surface area over which the Sun’s rays are distributed. Solar Energy Reaching the Earth Varies Solar Energy Reaching the Earth Varies • Third cause of uneven warming is varying albedo of earth’s surface. • Albedo: The percentage of incoming sunlight reflected from a surface – White/light areas (polar ice caps, glaciers) reflect more light back to the atmosphere than dark areas (oceans) Earth’s Tilt Causes Seasonal Changes in Climate • Earth tilts on its axis of rotation: 23.5° Think-Pair-Share • Which of the following is the correct order of atmospheric layers starting from the Earth’s surface? A. Thermosphere, stratosphere, troposphere, mesosphere, exosphere B. Exosphere, troposphere, mesosphere, stratosphere, thermosphere C. Mesosphere, stratosphere, thermosphere, exosphere, troposphere D. Thermosphere, troposphere, stratosphere, exosphere, mesosphere E. Troposphere, stratosphere, mesosphere, thermosphere, exosphere Think-Pair-Share • Which of the following is the correct order of atmospheric layers starting from the Earth’s surface? A. Thermosphere, stratosphere, troposphere, mesosphere, exosphere B. Exosphere, troposphere, mesosphere, stratosphere, thermosphere C. Mesosphere, stratosphere, thermosphere, exosphere, troposphere D. Thermosphere, troposphere, stratosphere, exosphere, mesosphere E. Troposphere, stratosphere, mesosphere, thermosphere, exosphere Think-Pair-Share • Which of the following contributes to the unequal heating of the earth? I. Variation in the angle of sunlight that reaches the earth II. Variation in the amount of surface area over which the sun’s rays are distributed III. Variation in the amount of sunlight reflected from the clouds. A. I only B. I and II only C. II and III only D. III only E. I, II, and III Think-Pair-Share • Which of the following contributes to the unequal heating of the earth? I. Variation in the angle of sunlight that reaches the earth II. Variation in the amount of surface area over which the sun’s rays are distributed III. Variation in the amount of sunlight reflected from the clouds. A. I only B. I and II only C. II and III only D. III only E. I, II, and III Air Currents • Explain how the properties of air affect the way it moves in the atmosphere • Identify the factors that drive atmospheric convection currents • Describe how the Earth’s rotation affects the movement of air currents • Explain how the movement of air currents over mountain ranges affects climate Properties of air • 4 properties determine how air flows in the atmosphere – Density – Water vapor capacity – Adiabatic heating or cooling – Latent heat release Air density • Density: the mass of all molecules in the air in a given volume • Less dense air rises – Warm air has a lower density than cold air • More dense air sinks • Warm air rises Water Vapor Capacity • Water vapor capacity: the potential for an air mass to hold moisture • Warm air has the potential to hold more moisture than cool air • Saturation point: the maximum amount of water vapor in the air at a given temperature • When temperature of air falls, its saturation point decreases, and water vapor condenses into liquid water. Clouds form and precipitation occurs. Water Vapor Capacity Adiabatic Cooling/Heating • As air rises higher in the atmosphere, the pressure on it decreases • The lower pressure allows the rising air to expand in volume, and this expansion lowers the temperature of the air. • This cooling effect is known as adiabatic cooling. • When air sinks in the atmosphere, the opposite occurs, and the temperature of the air rises. • This heating effect is known as adiabatic heating. Latent Heat Release • Latent heat release: the release of energy when water vapor in the atmosphere condenses into liquid • Whenever water vapor in the atmosphere condenses, the air will become warmer and rise in the atmosphere. Atmospheric Convection Currents • Atmospheric convection currents: global patterns of air movement that are initiated by the unequal heating of the earth. • Warm, humid air rises, cools, and then sinks as cooler, drier air. Idealized Model of Convection Currents However, the earth is spinning • The Coriolis effect, the deflection of an object’s path due to the rotation of the Earth, impacts these idealized cells Model of Earth’s Climate Cells (with prevailing wind directions) Polar Cell Ferrell Cell Hadley Cell Hadley Cell Ferrell Cell Polar Cell Climate Cells • Hadley cell: convection current in the atmosphere that cycles between the equator and 30° N and 30°S • Ferrell Cells: convection current in the atmosphere that lies between the Hadley and Polar cells • Polar Cells: Convection current in the atmosphere formed by the air that rises at 60°N and 60°S and sinks at 90°N and 90°S • ITCZ: Intertropical convergence zone, the area at the equator where the warm Hadley cell air rises and precipitation falls. – Characterized by dense clouds and intense thunderstorms Rain Shadow Effect • Mountains cause air to be forced upward to pass over them. • As the air rises, its saturation point drops, and it rains. • This causes a dry region on the leeward size of a mountain range as a result of humid winds from the ocean causing precipitation of the windward side. Rain Shadow Effect Think-Pair-Share • Temperature change in adiabatic heating occurs due to: A. B. C. D. E. Water vapor condensing A pressure increase Absorption of sunlight A pressure decrease A volume increase Think-Pair-Share • Temperature change in adiabatic heating occurs due to: A. B. C. D. E. Water vapor condensing A pressure increase Absorption of sunlight A pressure decrease A volume increase Think-Pair-Share • Which is the correct order of the convection cells, starting from the equator? A. Polar, Ferrell, Hadley B. Ferrell, Hadley, Polar C. Polar, Hadley, Ferrell D. Hadley, Ferrell, Polar E. Hadley, Polar, Ferrell Think-Pair-Share • Which is the correct order of the convection cells, starting from the equator? A. Polar, Ferrell, Hadley B. Ferrell, Hadley, Polar C. Polar, Hadley, Ferrell D. Hadley, Ferrell, Polar E. Hadley, Polar, Ferrell IP • Given the map that is passed out – Diagram the three atmospheric convection cells – Do some research, and diagram the major ocean currents