Chapter 4 Feb 7 PowerPoint Slides.pptx

Chapter 4 The Atmosphere and Earth’s Energy Budget Announcements: Cengage Chapter 4 is due February 11th at 11:59 PM Exam 1 is February 28th Chapter Objectives By the end of this chapter, you should be able to: 04.01 Explain four characteristics of our atmosphere that support life on Earth. 04.02 Li...

Chapter 4 The Atmosphere and Earth’s Energy Budget Announcements: Cengage Chapter 4 is due February 11th at 11:59 PM Exam 1 is February 28th Chapter Objectives By the end of this chapter, you should be able to: 04.01 Explain four characteristics of our atmosphere that support life on Earth. 04.02 List the four most abundant atmospheric gases, and explain why two are most important to life on Earth. 04.03 Explain the ways that solar energy interacts with Earth’s atmosphere and surface. 04.04 Describe how the solar energy that reaches Earth’s surface is transferred to the atmosphere. Chapter Objectives By the end of this chapter, you should be able to: 04.05 Discuss the processes and important roles that water plays in heat transfer. 04.06 Outline the characteristics of the troposphere, stratosphere, and ionosphere. 04.07 Describe the enhanced greenhouse effect and how it contributes to increasing the Earth’s average temperature. 04.08 Explain the major inputs, outputs, and processes in Earth’s energy budget and what energy balance means. 4-1 The Nature of Our Atmosphere 99% of air is in first 30 km (18.6 miles) Skin of an apple Density decreases with altitude Atmospheric composition Nitrogen Oxygen Argon Carbon dioxide 4-1 The Nature of Our Atmosphere (4.2) (2 of 10) Table 4.1 Composition of the Atmosphere Near the Earth’s Surface Permanent Gases GAS SYMBOL Variable Gases PERCENT(BY VOLUME) DRY AIR GAS (AND PARTICLES) SYMBOL PERCENT (BY VOLUME) PARTS PER MILLION(PPM)* Nitrogen N2 78.08 Water vapor H2O 0 to 4 Oxygen O2 20.95 Carbon dioxide CO2 0.0418 418 Argon Ar 0.93 Methane CH4 0.000185 1.85 Neon Ne 0.0018 Nitrous oxide N20 0.000033 0.33 Helium He 0.0005 Ozone O3 0.000007↑ 0.04↑ Hydrogen H 0.00006 Particles (dust, soot, etc.) 0.000001 0.01-0.15 Xenon Xe 0.000009 Chlorofluorocarbons(CFCs) 0.00000002 0.0002 *For CO2, 418 parts per million means that out of every million air molecules, 408 are CO 2 molecules. †Stratospheric values at altitudes between 11 and 50 kilometers are about 5 to 12 ppm.  4-1 The Nature of Our Atmosphere Aerosols are tiny solids or liquids suspended in the atmosphere— including dust, pollutants, and droplets or crystals of chemicals. Particulates (a variety of aerosols) are solid particles in the air. Pollutants are harmful aerosols and gases that are potential health hazards depending on their concentration in the air. 4-1 The Nature of Our Atmosphere Ozone forms in the upper atmosphere when incoming ultraviolet radiation from the sun splits an oxygen molecule into two free oxygen atoms (O). Ozone (O3) Ozone in the upper atmosphere protects us from damaging UV radiation Ozone absorbs large amounts of UV The ozone hole refers to roughly circular zones in the polar stratosphere where the ozone concentration is lower than expected. Concentration lower than expected Ozone destroyed by CFCs and NOx The Greenhouse Effect What is the Greenhouse Effect? Do you think it is a good or bad thing? 4-1 The Nature of Our Atmosphere The greenhouse effect: 4-1 The Nature of Our Atmosphere Atmospheric layering by temperature characteristics Troposphere—closest to Earth’s surface Nearly all weather takes place here Water vapor and particulates Temperature normally decreases with height Normal (environmental) lapse rate 6.5°C/1000 meters, 3.6°F/1000 feet Tropopause—boundary with the stratosphere 4-1 The Nature of Our Atmosphere Atmospheric layering by temperature characteristics Stratosphere Ozone layer Mesosphere Thermosphere Temperatures increase to 1100°C (2000°F) 4-2 Energy Transfer Processes Radiation: All objects with a temperature above absolute zero radiate energy. Shortwave Terrestrial The dominant source of atmospheric heat is terrestrial radiation, and the atmosphere mainly heats from the Earth’s surface upward. Conduction: Energy transfer between two objects in contact with each other 4-2 Energy Transfer Processes Convection: When parcels of air are heated, they expand in volume and become less dense than the surrounding air, causing them to rise Advection: Horizontal transfer of heat Latent Heat Exchange: energy transfer that occurs with changing state of matter 4-2 Energy Transfer Processes Latent Heat Exchange: energy transfer that occurs with changing state of matter