Atmosphere • Video Earth is beautiful. • Atmosphere
Atmosphere • Earth’s atmosphere ~ 800 Km thick • Magnetosphere
Atmosphere • earths
Atmosphere • Primitive earth
Atmosphere • The primeval atmosphere • gases from volcanic activity • water vapor, carbon dioxide, sulfur oxides, nitrogen, argon • Early water vapor condensed & precipitated to form the oceans. • Carbon dioxide and sulfur oxides dissolved in ocean water. • Photosynthesis “free” oxygen escaped to the atmosphere. • sunlight • 6CO2 + 6H2O → C6H12O6 + 6O2
Atmosphere • Current atmosphere thinner than earlier history • 78% nitrogen, 21% oxygen, 0.93% argon • The remaining 0·07% Trace gases: • 0·03% carbon dioxide • hydrogen, helium, neon, methane, ozone • Amount of water vapor in the atmosphere is variable, with a maximum of about 4%. • Suspended solid particles dust, ash, pollen
Atmosphere • Where else such earth-like conditions exist?
Comparing Atmospheres • Goldie locks!
Atmosphere • earths
Atmosphere • hh
Atmosphere • Atmospheric layers ~ Temperature and Composition • Exosphere 500 - 800 ? Km T • Thermopause • Thermosphere 80-500 Km T • Ionosphere lower section of Thermosphere • Satellites, Space station, radio waves • Mesopause • Mesosphere 48-80 Km T • 1% ˃ gases • meteors • Statopause • Stratosphere 11-48 Km T • 24% of gasses mostly O3 • Ozone Layer • Tropopause • Troposphere 0-11Km T • 75% of gases most of H2O vapor • Weather Sphere
Review • What are the two most abundant gases in the atmosphere today? • N2 78% and O2 21% • Compare and contrast primeval and the current atmospheres. • O2 not present in primeval atmosphere • What process produced the “free Oxygen”? • Photosynthesis • How are atmospheric layers described. • Temperature and composition • Describe the temperature pattern/behavior of the atmosphere. • Decrease & Increase alternately with increase in altitude • Describe mass distribution pattern of the atmosphere. • Decrease with increase in altitude
Review • Describe the behavior of Temperature in the Troposphere. • T decreasing with altitude • What is the warmest temperature on the graph? • 15 °C • In which layer is it? • Troposphere • What is the Temperature of Stratosphere at 48 Km? • Zero °C • At what altitude does Mesosphere exhibit Temp of – 45 °C? • About 65 Km • What is happening at the lower section of the Thermosphere? • Ionized gas ~ Auroras
Atmosphere • OZONE • O3 in stratosphere • Absorbs sun’s UV radiation • Protective shield • Natural production and destruction of Ozone Sun UV O2 O O + O2 O3Production O O2 Destruction
OZONE • Ozone production vs. destruction • Tilt of the earth’s axis and intensity of radiation • More in winter More in summer
OZONE • Dubson Units • Unit for measuring Ozone Thickness • Earth’s average atmospheric ozone is 300 D.U. • Ozone Depletion • Thinning of ozone layer • 1985 Ozone Hole over Antarctica
OZONE • CFCs and Ozone Destruction/Depletion
OZONE • Another CFC cycle
OZONE • CFC affect on the Ozone • sun • CFC free Chlorine • Cl + O3Cl O + O2 • Cl O + O free Cl + O2 • One free Chlorine + 100,000 Ozone gases • Destruction/depletion of ozone layer
OZONE • Montreal Protocol • 24 + 173 nations • Global ban of CFC
OZONE • In 1979—when scientists were just coming to understand that atmospheric ozone could be depleted—the area of ozone depletion over Antarctica grew to1.1 million square kilometers, with a minimum ozone concentration of 194Dobson Units. In 1987, as the Montreal Protocol was being signed, the area of the hole reached 22.4 million square kilometers and ozone concentrations dropped to109 DU. By2006, the worst year for ozone depletion to date, the numbers were 29.6 million square kilometers and just 84 DU. By2011, the most recent year with a complete data set, the hole stretched 26 million square kilometers and dropped to 95 DU. • According to NASA scientists, “The Antarctic hole is stabilizing and may be slowly recovering. The focus now is to make sure that it is healing as expected. The international agreement likely saved the world from an environmental crisis.
OZONE U.S. Ozone map
OZONE • UVA & UVB radiation • Marine Life • protected by water • Marine plants produced O2 • O2 in the atmosphere • Ozone Layer formation • Land organisms 450 M.Y.A
OZONE • Ozone Depletion & Health Issues • UVA & UVB radiation • Skin cancer • Cataract • Asthma
OZONE • Types of Ozone • Stratospheric Ozone ~ good ozone • Tropospheric / Urban Ozone ~ bad ozone ! • Smog • Health Issues
SMOG • Worst smog ever in Beijing 2013
OZONE • Green Movement
OZONE • Ozone Layer 104 • HW: EPA Ozone Puzzle
OZONE • Stratospheric ozone is typically measured in Dobson Units (DU), which is the number of molecules required to create a layer of pure ozone 0.01 millimeters thick at a temperature of 0 degrees Celsius and an air pressure of 1 atmosphere (the pressure at the surface of the Earth). The average amount of ozone in Earth’s atmosphere is 300 Dobson Units, equivalent to a layer 3 millimeters (0.12 inches) thick—the height of 2 pennies stacked together.
Modes of Energy Transfer • As much as we want for ozone to block/absorb solar radiation UVs, however we need solar energy to keep our planet at an average 15°C/58°F temperature. • How long does it take for solar energy to reach us? • 8 minutes and 20 seconds • How does solar energy travel to reach our planet? • In form of Radiation
Explore • The first number to know is the speed of light in a vacuum, which is 300,000 km/s. Next, you need to know the average distance from the Sun to the Earth, which is 150 million km. Divide the distance by the speed of light and you have 500 seconds for light to arrive on Earth. Finally, divide 500 seconds by 60 to get the number of minutes and you have 8 minutes and 20 seconds.Read more: http://www.universetoday.com/15021/how-long-does-it-take-sunlight-to-reach-the-earth/#ixzz2J6jBcr00
Modes of Energy Transfer • Radiation • energy travels through vacuum ( no particles ) • energy moves by itself • The energy from the sun that reaches the Earth's in the form of electromagnetic waves (photons/light waves).
Modes of Energy Transfer • conduction • Transfer of energy from one particle to another • Collision and transfer • Solid • Gas
Modes of Energy Transfer • Convection • Transfer of energy by each particle away from the energy source • Liquid and gas
Electromagnetic Waves • ghg
Modes of Energy Transfer • Not all of the solar energy that passes through the ozone will heat up the earth. • Absorption, reflection, refraction, scattering
Modes of Energy Transfer • And how is this heat kept? • The Blanket effect!!!!! • No heat by itself but act as a heat absorber and insulator. • Earth’s atmospheric gases act as a blanket.
Greenhouse gases • Although all gas particles absorb energy, some gases keep this absorbed energy longer and re-radiate/release it as heat. • These gases are called Greenhouse gases.
Greenhouse Gases • What is the Greenhouse Effect? • High frequency UV • Lower frequency “Heat” • Absorption by air ( gases)
Greenhouse Gases • CO2, CH4, CFC, O3, N2O, H2O vapor • Increase/Decrease in GH gases • Increase/Decrease in Global Temperatures
Global Levels of CO2 • Global Warming • Textbook page 380 • Graph & Questions • Find CO2 for year 2013
Greenhouse concept • Here is the explanation of a greenhouse! • The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases. • Solar radiation at the frequencies of visible light largely passes through the atmosphere to warm the planetary surface, which then emits this energy at the lower frequencies of infrared thermal radiation. Infrared radiation is absorbed by greenhouse gases, which in turn re-radiate much of the energy to the surface and lower atmosphere. The mechanism is named after the effect of solar radiation passing through glass and warming a greenhouse, but the way it retains heat is fundamentally different as a greenhouse works by reducing airflow, isolating the warm air inside the structure so that heat is not lost by convection.
Global Warming • gj
Global Warming & Ice Age • Alternate & natural long term episodes • Global cooling and warming
Global Warming Trend • Global Warming • 1500s slow increase • 1700s faster • 20th century
Causes & Effects • Solar activity ~ radiation out put • Volcanism ~ CO2 vs. SO2 & Ash clouds • Orbital shape ~ circular vs. elliptical
Causes & Effects • Human activity ~ • Industrial Revolution 1700s • Use of Fossil Fuels ~ CO2 • increase/speed intensity • * CH4