GLY6061 Geoscience Systems

1. GLY6061 Geoscience Systems http://vortex.ihrc.fiu.edu/GLY6061/GLY6061.htm https://canvas.instructure.com/courses/1239163 Lecture 1 Atmospheric Radiation Energy Budget How the atmosphere system is driven?

2. Earth-Sun relationship The Changing Seasons Are Due to the Tilt of Earth’s Axis

5. Transport by atmospheric motion and ocean currents Net transport by atmosphere and ocean Ocean currents Transient motion Atmospheric motions

6. Forms of Energy Kinetic energy: Energy associated with motion. Potential energy: Energy stored within a physical system. It has the potential to be converted into other forms of energy, such as kinetic energy, and to do work in the process. Heat (symbolized by Q): energy transferred from one body or system to another due to a difference in temperature. Mechanisms of Energy Transfer 1. Conduction: transfer of heat through electron and molecule collisions. 2. Convection: heat transfer that involves motion or circulation.

7. 3. Radiation: in the form of electromagnetic waves

8. Solar radiation Electromagnetic Radiation

9. Laws of blackbody radiation 1. Plank’s law 6000K 300K 2. Wien’s displacement law Gray body:

10. What Happens to Incoming Solar Radiation Selective absorption and emission of atmospheric gases 1. Energy level of atoms or molecules Quantum jump: transition between different energy levels 2. Different energy form of a molecule or atom

11. a. Rotational energy CO Rotational energy transition can happen as long as a photon’s wavelength is shorter than 1 cm, usually associated with microwave wavelength. b. Vibrational energy Polar molecule has permanent dipole Non-polar molecule does not have permanent dipole.

12. Vibrational energy level transition requires a photon's wavelength shorter than 20 micrometer, usually in the infrared band. Vibration and rotation sometimes combine together to form vibration- rotation mode, the transition between vibration-rotation modes also involves certain frequencies.

13. c. Photodissociation Solar ultraviolet photon For photodissociation to occur, the wavelength of a photon must be in the ultraviolet band. To dissociate Oxygen the wavelength of radiation must be shorter than 200 nm. Ozone is a loosely bonded molecule. To dissociate a Ozone molecule, the frequency of a photon can be as low as 300 nm.

14. d. Electronic excitation 1st Shell 2nd Shell Electrons may be excited from one shell to another shell by a photon with a sufficiently high energy level. The wavelength is usually shorter than 1 micrometer. e. Photoionization To photoionize a molecule requires the radiation with a wavelength shorter than 100 nm. Photoelectron

15. M Photoionization Electronic excitation overlap Almost all solar radiations shorter than ultraviolet are used up in the upper layer for photoionization, electronic excitation, and molecule dissociation. Since most of solar energy is in the visible band, they have nothing to do with molecule vibration and rotation transition, so solar radiation can reach Earth's surface almost without any attenuation. On the other hand, terrestrial radiation in the infrared band, which is involved with atmospheric molecule vibration and rotation transitions, can be absorbed by the atmosphere to cause greenhouse effect.

16. Highly un-reactive greenhouse gases containing bonds of fluorine-carbon or fluorine-sulfur, such as Perfluorocarbons (CF4, C2F6, C3F8) and Sulfur Hexafluoride (SF6). These trace gases have strong absorption lines right in the atmospheric window.

17. Greenhouse effect: shortwave solar radiation is nearly transparent to the atmosphere, but longwave terrestrial radiation is trapped by greenhouse gases, causing the increase of surface temperature.

19. Radiative Equilibrium model

20. Too cold σ: emissivity e=0 ----> radiative equilibrium model. e=1----> I=B In the real atmosphere, the absorbing materials are distributed continuously in the vertical. These include clouds, greenhouse gases such as water vapor, co2, O3,etc

21. Effects of atmospheric convection If the Earth system were in a radiative equilibrium only, it would not be in a dynamic equilibrium because the air near surface will warm up by contacting with hot surface, thus, convection will happen.The situation is further complicated by the phase change of water. Difference between convection and advection

22. Heat Budget of Earth’s Atmosphere

24. Composition of the Atmosphere

25. Carbon Dioxide Variable Components of the atmosphere Water Vapor 0-4% by volumn

26. Aerosol - fine solid or liquid particles suspended in the air (0.001 to 10 )

27. Ozone 10-50 km (stratosphere) Formation of Ozone Sustaining Ozone Depletion of Ozone

28. Ozone Ozone Depletion

29. The Ozone Hole Ozone concentration drops sharply over Antarctica

30. The Ozone Hole Cold air -80C Polar vortex 1. Polar winter leading to the formation of circumpolar winds to develop the polar vortex which isolates the air within it. 2. Cold temperatures; cold enough for the formation of Polar Stratospheric Clouds. As the vortex air is isolated, the cold temperatures persist. 3. The chlorine reservoir species HCl and ClONO2 become very active on the surface of the polar stratospheric clouds. The most important reactions are:

31. Protecting the atmosphere’s ozone layer An international agreement known as the Montreal Protocol on substances that deplete the Ozone Layer was concluded under the auspices of United Nations in late 1987. Global Ozone Recovery Predictions

32. Thermal Structure of the Atmosphere Temperature Temperature measures the average kinetic energy of molecules and atoms as they move. Thermal Structure of the Atmosphere