1 / 17

Mid-term review 1

Mid-term review 1. Chapter 1. 1. Weather and Climate. Weather: state of the atmosphere at a given time and place. It is constantly changing. Climate: “average” weather conditions. Climate is what you expect, but weather is what you actually get. 2. Four “Spheres” in the Earth System:.

harrison-mcintyre
Download Presentation

Mid-term review 1

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Mid-term review 1 Chapter 1 1. Weather and Climate Weather: state of the atmosphere at a given time and place. It is constantly changing. Climate: “average” weather conditions Climate is what you expect, but weather is what you actually get. 2. Four “Spheres” in the Earth System: Geosphere, Atmosphere, Hydrosphere, Biosphere 3. Systems A group of interacting parts (components) that form a complex whole.

  2. Open System: Energy and Matter can be exchanged between systems Closed System: Exchange of Matter greatly restricted, but may allow exchange of energy Isolated System: No Energy or Matter can be transferred in or out of the system 4. Feedback Processes in one system influences processes in another interconnected system by exchange of matter and energy. Positive Feedback: Change in one system causes similar change in the other system. Can cause runaway instability. e.g., water vapor feedback, ice cover feedback Negative Feedback: A positive change in one system causes a negative change in the other. e.g., cloud cover feedback

  3. 5. Composition of the Atmosphere Major components: Nitrogen (N2), Oxygen (O2), Argon (Ar), Carbon dioxide (CO2), Minute trace gases: water vapor (H2O),Methane (CH4), Ozone (O3), Nitrous Oxide (N2O) Variable components: Water vapor, Aerosol, Ozone Aerosol: direct and indirect effect Ozone: depletion and ozone hole 6. Extent of the Atmosphere Pressure: Force F acting on unit area due to the weight of the atmosphere. Surface atmospheric pressure: 1000 hPa or 1000 mb Temperature

  4. Thermal Structure of the Atmosphere Troposphere • Averaged Surface temperature is 288.16K, or 15C. • Decreases 6.5C per km up to 11 km (lapse rate). • Nearly all weather happens in this layer. • Height of the tropopause varies with latitude with an average of 10 km. Inversion: Negative lapse rate, temperature increases with height. Stratosphere Temperature is constant in the lower part of the layer, and then, increases with height due to O3 absorption of solar UV. ~ 99% of the atmosphere is below the stratopause. Mesosphere Temperature decreases with height in this layer Thermosphere Temperature increases greatly because air absorbs sunlight.

  5. Chapter 2 1. Sun-Earth relationship Earth’s motion, Seasons, Earth’s orientation, Solstices and Equinoxes 2. Forms of energy Kinetic energy Potential energy Heat 3. Mechanisms of Energy Transfer Conduction, convection, and radiation 4. Laws of blackbody radiation Stefan-Boltzman law, Wien’s displacement law, Plank’s law 6000K 300K

  6. 5. Selective absorption and emission of atmospheric gases 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.

  7. 6. 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. 7. Atmospheric window 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. Clouds can also absorb longwave radiation in the atmospheric window.

  8. 8. Solar constant: incoming solar radiation per unit area at the top of the atmosphere 9. Radiative Equilibrium, Radiative-covection Equilibrium 10. Heat Budget of Earth’s Atmosphere

  9. 11. Latitudinal energy balance 12. Transport by atmospheric motion and ocean currents

  10. Chapter 3 1. Air Temperature Isotherms Temperature gradient 2. Controls of Temperature Differential heating of land and water; Ocean currents; Altitude Geographic position; Cloud cover and albedo

  11. 3. Daily Cycles of Air Tmperature (diurnal) What controls the diurnal variation? 4. Heat island effect • Buildings absorb and store more solar radiation. • City surface results in reduction of evaporation. • Heat sources from heating system, air-conditioning, and industry. • Air pollution 5. Temperature measurement Maximum and minimum temperature Instrument shelters 6. Heat stress and wind chill Heat stress is caused by high temperature and high humidity. Wind chill is the cooling power of moving air.

  12. Chapter 4 1. Phase change and latent heat 2. Equation of state, gas law of dry air 3. Measuring water vapor in the air Water vapor pressure Mixing ratio, r Moist virtual effect Virtual temperature 4. Saturation Saturated water vapor pressure, E=E(T)

  13. 5. Relative humidity, h 6. Dew-point 7. Internal energy U Energy associated with the random, disordered motion of molecules. U=U(T) 8. Hydrostatic balance: the balance between upward pressure gradient force and downward gravitational force. 9. First law of thermodynamics in the atmosphere The change in internal energy of a system is equal to the heat added to the system minus the work done by the system. 10. Dry adiabatic process Lifting mechanisms 11. Adiabatic lapse rate Lapse rate of ambient environment 12. Lifting condensation level (LCL)

  14. 13. Moist adiabatic process 14. Moist adiabatic lapse rate 15. Reversible and Pseudo-saturated adiabatic process 16. Rain shadow effect 17. Potential temperature Potential temperature is conserved during the dry adiabatic process since it considers the fact that the temperature decreases with height due to air parcel expansion. 18. Skew T-logP diagram

  15. Level of Free Convection (LFC) Limit of Convection (LOC) Convective Inhibition (CIN)

  16. 19. Atmospheric Stability The atmosphere is unstable if a parcel at equilibrium is displaced slightly upward and finds itself warmer than its environment and thus continues to rise spontaneously away from its starting equilibrium point. The atmosphere is stable if a parcel at equilibrium is displaced slightly upward and finds itself colder than its environment andtherefore sink back to its original equilibrium point. Absolute instability Conditional instability Absolute stability

  17. Using potential temperature to determine atmospheric stability and instability < = < = = = Unstable Neutral Stable

More Related