Transcript Atmosphere
BELL RINGER 11/20/12 Create a bubble map of all the things you know about the atmosphere. ATMOSPHERIC STRUCTURE AND COMPOSITION DEFINITIONS Atmosphere: The thin envelope of gases surrounding the earth Highly compressible Density decreases rapidly with height Air: A mechanical mixture of gases and aerosols THE ATMOSPHERE Atmosphere = the thin layer of gases around Earth Provides oxygen Absorbs radiation and moderates climate Transports and recycles water and nutrients 78% N2, 21% O2 Minute concentrations of permanent (remain at stable concentrations) gases Variable gases = varying concentrations across time and place Human activity is changing the amount of some gases CO2, methane (CH4), ozone (O3) THE FORMATION OF OUR ATMOSPHERE! STEP 1: SUPERNOVA EXPLOSION The formation of Earth with an atmosphere made of hydrogen and oxygen. http://www.mydigitallife.info/wp-content/uploads/2007/05/supernova_sn2006gy.jpg STEP 2: SOLAR WIND The first atmosphere blew away. http://astroprofspage.com/wpcontent/uploads/2006/11/magneto.jpg STEP 3: VOLCANIC ERUPTIONS Solid surface of the earth was formed and many gases such as nitrogen, carbon dioxide, water vapor, and sulfur dioxide are released forming a second atmosphere. http://cache.virtualtourist.com/1719818Volcanic_eruption_in_Vatnajokul_glacier-Iceland.jpg COOLING OF THE EARTH’S SURFACE AND THE ATMOSPHERE It rains and rains and rains. LIGHTNING AND TORRENTIAL STORMS Lightning breaks apart water molecules in the air, creating free oxygen which helps to form ozone. PRESENCE PHOTOSYNTHESIZING ORGANISMS Carbon dioxide in the atmosphere decreases and oxygen levels increase. ORIGIN OF THE ATMOSPHERE Volcanoes release H2, CO2, H2O, N2, NH3, CH4 No O2 or O3, so no land organisms! Simple aquatic plants took in CO2 and released O2 to atmosphere via photosynthesis O3 (ozone) formed from the O2 COMPOSITION OF THE ATMOSPHERE: GASES IN ATMOSPHERE Water Vapor 0.0-4.0% 0.93% .003% 0.01% 21% 78% Trace Gases Neon Helium Methane Krypton Hydrogen Ozone Xenon WHY ARE TRACE GASES IMPORTANT Water Vapor Varies with season, altitude of particular mass of air and surface features beneath the air Air over desert is dries than over ocean Source of clouds, rain and snow Regulates amount of energy the atmosphere absorbs Regulates temperature, source of precipitation, helps create weather WHY ARE TRACE GASES IMPORTANT? Carbon Dioxide- regulates energy in the atmosphere (Green house gas), Amplifies heating of atmosphere, plants need it for photosynthesis. Ozone rays (O3),- form of oxygen that blocks UV How is Ozone made? 1. sunlight splits an O2 molecule, forming 2 single O molecules 2. One new O atom collides with an O2 molecule 3. New O3 molecule formed SOLIDS IN THE ATMOSOSPHERE Salt Picked up from ocean spray Aids in cloud formation Dust Carried by the wind Aids in cloud formation Ice Formed from hail and snow 17.1 ATMOSPHERE CHARACTERISTICS Composition of the Atmosphere Human Influence • Emissions from transportation vehicles account for nearly half the primary pollutants by weight. AIR POLLUTION Any substance in the atmosphere that is harmful Sources include: Burning fossil fuels – coal and petroleum Temperature inversion can make it worse This is when warm air layers on top of cool air that contains pollutants trapping it and not letting it disperse PRIMARY POLLUTANTS LAYERS OF THE ATMOSPHERE: atmospheric layers separated by the variation of temperature patterns. p. 480 Pressure & Temperature as the altitude increases, the pressure decreases This is called an INVERSE relationship The atmosphere rapidly thins as you travel away from Earth until there are too few gas molecules to detect. ATMOSPHERIC PRESSURE • • • • Atmospheric Pressure Air pressure is the force air exerts per unit area. Air pressure is measured with a barometer. Air pressure decreases as altitude increases. You do not notice the pressure because you have always lived with it. ATMOSPHERIC AIR PRESSURE Atmospheric Layers there are 4 layers based on temperature changes Troposphere Is this something I should remember? YES!!! Stratosphere Mesosphere Thermosphere TROPOSPHERE Layer nearest Earth0-18 km We live in the troposphere. All weather and water vapor are in this layer. Clouds form in this layer Gets colder as you go up. Airplanes Fly Temperature drops as altitude increases, Density is the greatest in this layer of the Earth. Contains over 80% of the atmosphere More tan 50% of the atmosphere is located below 5.6km “The Troublesphere” STRATOSPHERE 11–50 km (7–31 mi) above sea level Temperature stays constant, then start to increase as altitude increases This is because there is a lot of ozone in the stratosphere and ozone absorbs the heat Home of the Ozone layer. Ozone layer is not constant. Changes began to be noticed in the ozone above Antarctica in the 1970’s. This is the layer that absorbs ultraviolet radiation and it becomes heated Planes will fly in lowest part of this layer to avoid storms This is warmer than the troposphere Drier and less dense, with little vertical mixing The troposphere and stratosphere together make up the lower atmosphere 99% of all atmospheric air is found here OZONE LAYER Lower portion of stratosphere From about 12 to 19 miles up. Varies seasonally and geographically High concentration of ozone (O3) Absorbs about 98% of the Sun’s UV(B) radiation OZONE LAYER Chlorofluorocarbons (CFCs), chemicals found mainly in spray aerosols heavily used by industrialized nations for much of the past 50 years, are the primary culprits in ozone layer breakdown In 1978, the United States, Canada and Norway enacted bans on CFC-containing aerosol sprays that damage the ozone layer. On August 2, 2003, scientists announced that the global depletion of the ozone layer may be slowing down due to the international regulation of ozonedepleting substances. OZONE LAYER Ozone occurs in two layers of the atmosphere. The ozone that is commonly associated with ozone depletion and the ozone “hole” is in the stratosphere, a layer that extends upward from about 10 to 30 miles (15 to 50 kilometers) above the earth. This “good” ozone shields life on earth from the sun's harmful ultraviolet rays (UV-b). The layer surrounding the earth's surface is the troposphere. Here, ground-level or "bad" ozone is an air pollutant that damages human health, vegetation, and many common materials. It is a key ingredient of urban smog. The troposphere extends from the surface to about 10 miles (15 kilometers) above the surface. Ground level, or “bad ozone”, is also called tropospheric ozone while “good ozone” is called stratospheric ozone. About 80-90% of all ozone in the atmosphere is found in the stratosphere. MESOSPHERE 50–80 km (31–56 mi) above sea level Coldest layer of the atmosphere at -90°C Temperature decreases as altitude increases Extremely low air pressure Coldest layer of the atmosphere Radio waves are reflected to Earth Meteors burn up in this layer, THERMOSPHERE Extends upward to 500 m (300 mi) Temperature increases with increasing altitude due to the absorption of very short-wave solar energy by oxygen. It is the hottest layer Aurora lights occur Contains electrically charged particles Satellites orbit space in this layer of Earth’s atmosphere. Ionosphere is the lower region which contains ions and reflects radio waves back to earth Exosphere is where the earth’s atmosphere blends with space. It is 1000s of kms above earth IMPORTANCE OF THE ATMOSPHERE Earth’s atmosphere makes conditions on Earth suitable for living things. The atmosphere is constantly changing as the gases move in and out of living things, the land, and the water. It works to trap the sun’s energy, move the heat around, and make it possible for life to exist. IMPORTANCE OF THE ATMOSPHERE Earth’s atmosphere traps energy from the sun, which allows water to exist in a liquid form. Allowing, water to exist in a liquid form, allows for life to happen, as water is essential for living things. Almost all of the Earth’s energy comes from the sun and is called radiant energy •most reaches the atmosphere and is reflected back to space •Some is absorbed by the Earth and is spread throughout the atmosphere as: •Radiation: transfer of energy in form of waves •Unlike conduction and convection, which need material to travel through, radiant energy can travel through the vacuum of space.