Atmosphere and Humans: Atmosphere and Humans AP Environmental Science Mark Ewoldsen, Ph.D. and Michael Zito www.ai.mit.edu/people/jimmylin/pictures/2001-12-seattle.htm


Atmosphere and Humans: Atmosphere and Humans The Atmosphere Pollution Greenhouse Effect Ozone Depletion


Atmosphere and Humans: Atmosphere and Humans The Atmosphere Origin of Modern Atmosphere Structure Composition Weather Pollution Greenhouse Effect Ozone Depletion


Origin of Modern Atmosphere: Origin of Modern Atmosphere original atmosphere surrounded the homogenous planet Earth and probably was composed of H and He second atmosphere evolved from gases from molten Earth H2O, CO2, SO2, CO, S2, Cl2, N2, H2, NH3, and CH4 allowed formation of oceans and earliest life modern Atmosphere evolved after Cyanobacteria started photosynthesizing oxygen produced did not reach modern levels until about 400 million years ago www.degginger.com/digitalpage.html


Composition : Composition Nitrogen (N2, 78%) Oxygen (O2, 21%) Argon (Ar, 1%) myriad of other very influential components are also present which include the Water (H2O, 0 - 7%), "greenhouse" gases or Ozone (O3, 0 - 0.01%), Carbon Dioxide (CO2, 0.01-0.1%),


Earth’s Atmosphere: compared to the size of the Earth (104 km), the atmosphere is a thin shell (120 km). Earth’s Atmosphere http://www.gsfc.nasa.gov/gsfc/earth/pinatuboimages.htm


AtmosphereLayers: Exosphere Thermosphere (Ionosphere) Mesosphere Stratosphere Troposphere Atmosphere Layers


Troposphere: Troposphere 8 to 14.5 kilometers high (5 to 9 miles) most dense the temperature drops from about 17 to -52 degrees Celsius almost all weather is in this region


Stratosphere: Stratosphere extends to 50 kilometers (31 miles) high dry and less dense temperature in this region increases gradually to -3 degrees Celsius, due to the absorption of ultraviolet radiation ozone layer absorbs and scatters the solar ultraviolet radiation ninety-nine percent of "air" is located in first two layers every 1000-m 11% less air pressure


Mesosphere: Mesosphere extends to 85 kilometers (53 miles) high temperatures again fall as low as -93 degrees Celsius called the middle atmosphere by scientists


Thermosphere: Thermosphere extends to 600 kilometers (372 miles) high temperatures go up as altitude increases due to the Sun's energy temperatures in this region can go as high as 2000 degrees Celsius known as the upper atmosphere


Exosphere: Exosphere starts at the top to the thermosphere and continues until it merges with interplanetary gases, or space (372 to 6200 miles) hydrogen and helium are the primary components and are only present at extremely low densities


Ionosphere: Ionosphere when solar energy is absorbed directly by air molecules, the atoms gain or lose electrons and become charged particles called ions many gas molecules at altitudes of 80 - 400 km (mesosphere and thermosphere) have electrically charged particles reflects many types of radio waves allowing them to bounce around the world


Types of Heat Transfer: Types of Heat Transfer Convection Conduction Radiation Heating water in the bottom of a pan causes some of the water vaporize into bubbles. Because they are lighter than the surrounding water, they rise. Water then sinks from the top to replace the rising bubbles. This up and down movement (convection) eventually heats all of the water. Heat from a stove burner causes atoms or molecules in the pan’s bottom to vibrate faster. The vibrating atoms or molecules then collide with nearby atoms or molecules, causing them to vibrate faster. Eventually, molecules or atoms in the pan’s handles are vibrating so fast it becomes too hot to touch. As the water boils, hear from the hot stove burner and pan radiate into the surrounding air, even though air conducts very little heat.


Importance of the Atmosphere: Importance of the Atmosphere Physicists physical properties and processes that take place between the radiant energy and atmospheric gases Chemists behavior of the chemical materials in the atmosphere the ways in which lightning causes the formation of substances chemistry of the ozone layer and of chemicals introduced from industrial processes


Slide16: Astronomers and space scientists the layer through which they must peer before entering the realms of space Meteorologists, climatologists and geographers lower layers of the atmosphere predicting the weather investigating climatic regions examine the effects of climate and weather on human society


Slide17: Sun High energy, short wavelength Low energy, long wavelength Ionizing radiation Nonionizing radiation Cosmic rays Gamma rays X rays Far ultraviolet waves Near ultraviolet waves Visiblewaves Near infrared waves Far infrared waves Microwaves TV waves Radio waves Wavelength in meters (not to scale) 10-14 10-12 10-8 10-7 10-6 10-5 10-3 10-2 10-1 1


Slide18: Energy emitted from sun (Kcal/cm2/min) 0 5 10 15 0.25 1 2 2.5 3 Wavelength (micrometers) Visible Infrared Ultraviolet


Slide20: Seasons on Earth


Distribution of Biomes: Distribution of Biomes


Weather: Weather Contribute to Weather Air temperature Air pressure Humidity Cloud cover Precipitation Winds Types of Weather Fronts Severe Weather


Air Temperature: Air Temperature As solar energy reaches the Earth, equatorial regions heat up more than the poles. Warm air and water at the equator travel poleward while cold air and water at the poles travel equatorward in an attempt to equalize this temperature contrast. It is the atmosphere's continual struggle for temperature balance that brings us our changing weather.


Slide24: http://www.usatoday.com/weather/tg/wglobale/wglobale.htm


Air Pressure: Air Pressure air pressure is caused by the weight of the air pressing down on the Earth, the ocean and on the air below the pressure depends on the amount of air above the measuring point and falls as you go higher air pressure changes with weather


… and Weather: … and Weather air in a high pressure area compresses and warms as it descends the warming inhibits the formation of clouds, meaning the sky is normally sunny in high-pressure areas haze and fog might form the opposite occurs in an area of low pressure


Precipitation: Precipitation air containing water vapor cools in atmosphere and therefore condenses to form droplets of liquid water Rain: liquid, falls, d >0.5 mm (sphere) Freezing Rain: occurs when drop touches frozen surface Sleet: ice pellets, d < 0,5 mm, begins as rain but enters air below freezing Snow: water deposits in hexagonal nuclei below freezing Snow Pellets: grains of ice, d = 2-5 mm Hail: 5-190 mm in diameter, concentric rings of ice


Winds: Winds horizontal wind moves from areas of high to low pressure speed is determined by differences in pressure Coriolis effect causes winds to spiral from high pressure zones and into low pressure zones www.iiasa.ac.at/Admin/INF/OPT/ Spring98/feature_story.htm


Slide32: Cell 3 South Cold, dry air falls Moist air rises — rain Cell 2 South Cool, dry air falls Cell 1 South Moist air rises, cools, and releases moisture as rain Cell 1 North Cool, dry air falls Cell 2 North Moist air rises — rain Cell 3 North Cold, dry air falls Polar cap Arctic tundra 60° 30° 0° 30° 60° Polar cap Evergreen coniferous forest Temperate deciduous forest and grassland Desert Tropical deciduous forest Equator Tropical rain forest Tropical deciduous forest Desert Temperate deciduous forest and grassland


Slide33: 60ºN 30ºN 0º 30ºs 60ºS Cold deserts Westerlies Forests Hot deserts Northeast trades Forests Equator Hot deserts Forests Southeast trades Westerlies Cold deserts


Slide34: The Rain Shadow Effect


Slide35: Mountain Ice and snow Altitude Tundra (herbs, lichens, mosses) Coniferous Forest Tropical Forest Deciduous Forest Tropical Forest Deciduous Forest Coniferous Forest Tundra (herbs, lichens, mosses) Polar ice and snow Latitude


El Nino – Typical surface ocean circulation: El Nino – Typical surface ocean circulation


El nino conditions: El nino conditions Normal El nino – strong counter-current


El Nino: Normal Conditions: Prentice Hall Textbook animation link El Nino: Normal Conditions


El Nino: El Nino Development: Prentice Hall Textbook animation link El Nino: El Nino Development


Slide40: Normal Conditions Cold water Warm water Thermocline SOUTH AMERICA Warm waters pushed westward AUSTRALIA EQUATOR Surface winds blow westward


Slide41: El Niño Conditions Cold water Thermocline Warm water Warm water deepens off South America SOUTH AMERICA Warm water flow stopped or reversed AUSTRALIA EQUATOR Drought in Australia and Southeast Asia Winds weaken, causing updrafts and storms


El Nino: La Nina: Prentice Hall Textbook animation link El Nino: La Nina


El Nino – weak Aleutian High : El Nino – weak Aleutian High


La Nina – strong Aleutian High: La Nina – strong Aleutian High


El nino - precipitation : El nino - precipitation


El nino - precipitation: El nino - precipitation


Slide47: Tropical rain forest (Manaus, Brazil)


Distribution of Biomes: Distribution of Biomes