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Chapter 37 The Atmosphere, the Oceans, and their Interactions Changing Temperatures 1. 2. Oceans are important for keeping Earth’s temperature and climate under control What does it mean that earth has large heat capacity? Slow to heat up or cool down Need a lot of heat/energy to heat or cool down the earth Especially true near water Fill in the Blank 3. ______________________________ __ is an example of a city with moderate temperatures because of the ocean. The Evolution of the Atmosphere 4. Hydrogen and Helium are believed to have been in the first atmosphere 5. Some scientists believe no oxygen was present 6. What caused the second stage in the formation of the atmosphere? a. b. c. Gases escaped through volcanoes/fissures 85% water vapor, 10% CO2, 5% nitrogen Still no free oxygen The Evolution of the Atmosphere 7. Free oxygen may not have appeared until green algae and stromatolites (basic plants) appeared *Why did oxygen come with the plants? 8. Free oxygen produced allowed an Ozone layer to form. 9. Ozone filters ultraviolet radiating which keeps the earth cool. 10. Heat keeps gas molecules from falling out of the air. 11. Air grows cooler and thinner at higher elevations 12. Density is greatest at the bottom due to gravity. Air Components 13. Air has weight and exerts pressure on the earth’s surface called atmospheric pressure 14. Weight of air on oceans keeps the ocean from boiling away. 15. Nitrogen (78%) and Oxygen (21%) are the most abundant gases in the air. 1. 2. Can you guess the next two gases? Argon & Carbon Dioxide Structure of the Atmosphere 16. The atmosphere is classified in layers 17. Weather occurs in the troposphere a. Contains 90 percent of atmosphere’s mass b. Extends 8 to 16 km up depending on region c. Temperature decreases gradually (at top = -50!) 18. Why do airliners fly at the top of this layer? a. Avoid weather b. Less bumpiness Structure of the Atmosphere 19. Stratosphere is above the troposphere a. b. c. goes up to 50 km Contains the ozone layer Temperature increases (-50 to 0)…. Why? 20. Mesosphere extends up to 80 km a. Temperature decreases again b. Meteor and rock fragments burn up here 21. Thermosphere extends up to 500 km a. Space shuttles orbit here b. Where auroras happen Structure of the Atmosphere 22. Ionosphere is an ion-rich area within the thermosphere and uppermost mesosphere a. b. Ions produced from interaction between solar radiation and atoms in the atmosphere Produces auroras near the magnetic poles 23. Above 500 km is the exosphere a. Very thin b. Merges into space Assignment Create a visual map of the atmosphere layers For each layers, use some sort of combination of pictures and colors to show the characteristics of that layer Example: The troposphere is where weather occurs so you could draw a thunderstorm happening in that layer See next slide Solar Energy THINK! Why are the areas near the equator warmer than the polar regions? 1. 2. More direct sunlight! Surface temperatures depend on the angle of the sun’s rays to the earth’s surface Being at an angle spread the same energy over a larger area. The Seasons 1. The US and Canada have distinct seasons because they have variations in the angle of the sun 2. Summer = Sun’s rays closest to perpendicular ( )on a spot on the earth 3. More oblique (at an angle) rays come 6 months later = winter! Seasons 4. 5. 6. 7. Earth is actually farthest from the sun when the Northern Hemisphere has summer Angles matter more than distance is SEASONS! Equinoxes - are days of equal hours of daylight and night (mid-Sept. & mid-March) At the poles there are 6 months with 24 hour days or nights Terrestrial Radiation 1. The earth absorbs some energy from the sun 2. Part is reradiated back into space = terrestrial (earth) radiation 3. Terrestrial radiation actually directly warms the lower atmosphere; why higher = colder Terrestrial Radiation 4. 5. 6. 7. Temperature depends on the net effect of radiation coming in and radiation going out Direct sunlight= surface absorbs more energy than it emits which causes the earth to warm Night is cooler because earth sends back more energy than it takes in Cloudy nights are warmer because clouds block incoming or outgoing radiation Where do the sun’s rays go? What happens to the majority of the sun’s radiation? What percent is reflected back into the atmosphere and back into space? What percent is absorbed in some part of the earth? What are some things solar radiation on earth is used for? Greenhouse Effect 1. What happens when the terrestrial radiation can’t get out? 2. Actually beneficial to a certain degree Keeps the earth warm Too much can be a problem 3. Largest gases involved in global warming? Water vapor! Carbon Dioxide – levels on the rise Methane & CFC’s 37.4 Driving Forces of Air Motion (Standard 5b) THINK! What is a convection current? Why do we call our ovens convection ovens? Warm air rises, cools down, then falls Creates a current that evenly cooks food 1. Convection currents in the atmosphere create wind a. How would you define wind? a. b. c. Air in nearly horizontal motion Wind is generated due to pressure differences in the atmosphere Difference in pressure between two spots called a pressure gradient 2. Underlying cause of air circulation is uneven heating of earth a. b. c. d. Air warmer at equator; warm air rises Cools as circulates to Poles; cold air falls Cooler air moves back toward equator If earth were still there would be one circulation pattern in the south one in the north Why don’t the air patterns on earth actually look like this? Answer: The rotation of the earth! 3. The earth rotates; affecting the air movement a. b. c. What would happen if you played catch on a merrygo-round Coriolis effect – apparent deflection due to the rotation of the earth Coriolis effect causes wind to go right in Northern hemisphere and left in Southern hemisphere i. ii. Faster wind = greater deflection Deflection greatest at poles; decreases at equator Global Circulation Patterns 1. Cells of circulation move heat over earth At equator air flows straight up a. i. ii. iii. Called doldrums Cool as air rises, causes rain Makes tropical forests found at equator Moves North or South b. i. ii. iii. iv. At ~30 degrees, cools enough to fall down Warms as it falls Creates hot, dry air Deserts characteristic Trade winds & Westerlies 2. Air moves south from the north and north from the south a. b. Deflected westward Produces trade winds 3. Air moving north from the north and south from the south a. b. Deflected eastward Produces Westerlies Other Winds 4. Polar regions have cold air a. b. Cold dry air meets warm, moist air at 60 degrees north and south Creates storms in these regions 5. Mountains, valleys, deserts, forests, bodies of water all influence how wind blows Oceanic Circulation Oceanic Circulation Lab Keep water in containers Clean up any spills Follow directions and be sure and mark which color ice cube is which Answer pre-lab questions, then come up and get the equipment and ice cubes you need Tuesday, February 10 Word: Relative humidity: ratio of the amount of water vapor in the air compared to the amount the air can hold at a given temperature Warm-Up: Which is more dense (sinks), cold water or warm water? Which is more dense, salty water or fresh water? How does that relate to ocean circulation? Philosophical Chairs You must participate at least once to get credit You must fill out the sheet and turn it in to get credit If you talk without being called on, you will get points docked Rules of Engagement Topic Statement Global warming is a natural thing and we should not be worried about its effects. Wednesday, February 11 Jet streams: high speed winds in the upper troposphere Warm-up: What animal did Al Gore say you should always rescue? Explain how a convection cycle is made. Ocean Circulation Two types of currents move the ocean Wind-driven surface currents Density-driven deep water currents Density is controlled by two things Temperature Salinity – how salty a mixture is Salinity Salinity is a measure of the amount of salts dissolved in 1000 g of seawater The ocean is about 3.5% salt Kept about the same by fresh water coming in and evaporation Layers of the Ocean Ocean has layers: surface zone, transition zone, and deep zone What are the characteristics of water as you go deeper? More pressure Colder Remembering your lab, which is more dense and sinks, cold or warm water? Which is more dense, salt water or fresh water? Surface Currents Wind effects water over a short distance Over a long distance Coriolis effect comes into play: Causes water to spiral in a circular gyre Clockwise in Northern Hemisphere Counterclockwise in Southern Gyres circulate heat around the world Warm water from Mexico moves up US East Coast Cold water from Alaska moves down along US West Coast Deep Water Currents Deep currents are driven by gravity Deep water flow like a large conveyor belt Starts at the north: Sea water freezes, leaves salt behind Increased salinity = increased density Water Sinks Deep water flows along bottom, creating conveyor belt – Starts in N. Atlantic, to Antarctica and back up