Chapter 4 Lecture Slides February 9th.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 Today’s Agenda: (10:10 AM – 10:25 AM) ~ Finish Chapter 4 Worksheet from Wednesday (10:25 AM – 10:45 AM) ~ Chapter 4 Lecture (10:45 AM – 11:00 AM) ~ Go Over Pra...

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 Today’s Agenda: (10:10 AM – 10:25 AM) ~ Finish Chapter 4 Worksheet from Wednesday (10:25 AM – 10:45 AM) ~ Chapter 4 Lecture (10:45 AM – 11:00 AM) ~ Go Over Practice Exam Answers 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? 4-2 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 4-3 Earth’s Energy Budget Earth’s energy budget - relationship between solar energy input, storage, and output within the Earth system. The energy budget accounts for incoming solar energy, what happens as it encounters Earth’s atmosphere, where it is absorbed and stored, and how outgoing energy is lost to space. Earth’s energy budget involves many factors, but it can be fairly well understood based on the most important processes. 4-3 Earth’s Energy Budget energy balance - the concept that the energy Earth receives from the sun is equaled (balanced) by return of that energy back to space, thus Earth has not continually increased or decreased in temperature over its history of billions of years. we know that Earth has not gotten continually warmer or colder throughout its planetary history. The energy balance is an example of dynamic equilibrium The Earth-atmosphere system is constantly trying to maintain a balance between the energy that reaches Earth from the sun and the energy that flows from Earth back out to space. Do all locations on Earth receive the same amount of insolation? 4-3 Earth’s Energy Budget The majority of locations on Earth have local energy budgets that are unbalanced between incoming solar radiation and outgoing terrestrial radiation. The insolation received at a particular place depends on latitude, daylight duration, and seasonal regime. The latitudes of 38° North and South divide approximate equatorward zones that receive a solar energy surplus and poleward zones that experience annual deficits 4-4 Air Temperature Heat—energy being transferred from one substance or medium to another because of temperature differences. Temperature—measure of the average kinetic energy of molecules in a substance. Temperature scales Fahrenheit scale (°F) Celsius scale (°C) Kelvin scale (K) What is absolute zero? What is 16 F in Celsius? Kelvin? What is 380K in Celsius? Fahrenheit? 4-4 Air Temperature Why would there be a change in insolation daily? Diurnal changes create daily temperature lag When is the sun highest in the sky? When is it the warmest part of the day? Minimum near sunrise Why? 4-4 Air Temperature Based on this images, how does cloud cover change air temperature?