GEU 0047: Meteorology Lecture 01 Introduction to weather and climate

1. GEU 0047: MeteorologyLecture 01Introduction to weather and climate

2. Web Resources • Online tutorials • Ahrens7 • World Weather Information Service • world's weather today • The Local Weather and Forecast • http://www.cwb.gov.tw/ • The NOAA National Weather Service • http://www.nws.noaa.gov/ • The GOES Weather Satellites • http://wwwghcc.msfc.nasa.gov/GOES/ • Satellites monitoring the natural resources • http://modis.gsfc.nasa.gov

3. Meteorology Overview • Topics • Observational Atmospheric Phenomena • Structure of the Atmosphere • Physical Dynamics* • Atmospheric Chemistry • Radiation and Heat Transfer • Remote Sensing* • Weather Forecasting* • Severe Weather • Global Climate Issues

4. Meteorology Overview • Meteorology – the study of the atmosphere and the involved processes that cause weather (mainly within the troposphere). • Study the meteorology = study the atmosphere, weather and climate. • Atmosphere – a region of gas about 0.25% of the earth’s diameter (contains 99% of the atmospheric mass.)

5. The Atmosphere • It is the medium in which the weather takes place which is a thin envelope of gases (a mixture) (which may contain suspended solid and liquid particles and clouds) which encircles the globe. • It functions to provide the essentials for life and orderly functions of physical and biological processes on the earth. (e.g. shields UV, gases for photosynthesis.

6. Table 1-1, p. 3

7. The Weather • Weather is the state of the atmosphere at a specific location and time. • It is described by temperature, cloudiness, visibility, precipitation, wind speed and direction, and humidity,… etc.

8. Fig. 1-CO

9. Atmos. is here! What season this image was most likely taken? Sirocco Fig. 1-2, p. 3

10. The Climate • Climate is the weather conditions at a locality averaged over a specific period (typically 30 years). • In descriptions, it also includes the departures (anomalies) from the average and extremes in weather (e.g., frequency of wet-dry spells, frequency of hail, average rainfall.

11. Condensation Evaporation Fig. 1-3, p. 5

12. The Grand Carbon Cycle Fig. 1-4, p. 5

13. The Keeling curve Fig. 1-5, p. 6

14. Hole? Dobson ? Fig. 1-6, p. 7

15. Fig. 1-7, p. 7

16. Evolution of the Atmosphere “BIG BANG” 1. First atmosphere -- one of cosmic gases: H2 - Hydrogen He - Helium CH4 - Methane NH3- Ammonia H2O - Water Vapor CO2 - Carbon Dioxide NOx - Oxides of Nitrogen

17. Second and Third Atmospheres High temperatures probably drove off primeval atmosphere. 2. Second Atmosphere: Nothing -- similar to the moon • Third Atmosphere: Developed from secondary sources such as outgassing from volcanoes, geysers, cracks, fissures, etc.. (gaseous emissions from solids or liquids, usually caused by exposure to high operating temperatures and/or altitude (low external pressure)

18. H2Ov - 68% CO2 - 13% N2 , N0x - 19% After the Earth cooled CO2 - 74% H2Ov - 15% N2 , NOx - 11% Evolution of the Atmosphere Composition of Volcano Effluent rain As the earth cooled, the water vapor condensed and created the oceans, etc. oceans

19. Evolution of the Atmosphere • First bacteria evolved maybe four billion years ago (anaerobic). • About 2-3 billion years ago green plants appeared in the oceans (algae). • Why oceans? Important for life because H2O screens out UV

20. Evolution of the Atmosphere Why oceans? • The cooling of the primordial Earth to the point where the outgassed volatile components were held in an atmosphere of sufficient pressure for the stabilization and retention of liquid water. • Comets, trans-Neptunian objects (TNO) or water-rich meteorites from the outer reaches of the asteroid belt colliding with a primordial Earth. • Biochemically through mineralization and photosynthesis. e.g. 4H2S + CO2 ―> CH4 + 2H20 + 4S (in the presences of sulfide-dependent bacteria and light energy) • Gradual leakage of water stored in hydrous minerals of the Earth's rocks.

21. Evolution of the Atmosphere • Photosynthesis: CO2 + sunlight + chlorophyll O2 + organic material However, time is needed for this to occur, Photodissociation (2H2O ―> 4H + O2)

22. 100 % CO2 50 % O2 0% 5 4 3 2 1 0 Evolution of the Atmosphere Faint young sun paradox Approximate Composition Billions of years before present

23. Evolution of the Atmosphere • Current Atmosphere • N2 - 78% Nitrogen • O2 - 21% Oxygen • Ar - 1% Argon • CO2 - 0.03% Carbon Dioxide • H2Ov - 0 to 4% Water Vapor • Particulates, Trace gases

24. Summary • Changes after plant life evolved: • CO2decreased via photosynthesis • O2increased via photosynthesis • Ar (Argon) increased via the radioactive decay of potassium • N2 ??????? --- Hmmm, a mystery! (Lavoisier named it azote, “without life”) • Homework #1: Please survey current theorems regarding the origin of nitrogen in modern atmosphere (Due 4 Oct.)

25. Vertical structure of atmosphere

26. = mass/volume = force/area Fig. 1-8, p. 10

27. 1mb = 1hPa = 100 Pascal 1Pascal = 1NT/m2 1NT = 1Kg ．1meter/sec2 Fig. 1-9, p. 10

28. Temperature profile Fig. 1-10, p. 11

29. Why hot-air balloon rises ? Fig. 4, p. 14

30. Table 1, p. 13

31. THE ATMOSPHERE • The atmosphere has two other attributes: • Homosphere – has the same mixing fraction of gases throughout. • Heterosphere – the gases settle out with the heavier gases at the lower part and the lighter at the top. Ionosphere – region where the gases are ionized by the sun’s UV and affect the propagation of radio waves.

32. (外逸層/外氣層) Fig. 1-11, p. 15

33. Role of ionosphere in radio communications Fig. 1-12, p. 16

34. Brief History of Meteorology • The book Meteorologica, written by Aristotle in 340BC, first described the sum knowledge on weather and climate. It also included topics in astronomy, geography and chemistry. • Instruments developed starting in the late16th century. The thermometer, barometer, hygrometer. The development of the telegraph provided routine weather observations.

35. Brief History of Meteorology • There were advances made in understanding wind flow and storm movement. This lead to produce crude weather maps with isobars in the late 1860’s. In the 1920’s, Norwegian scientists made advances in understanding air masses and weather fronts. In the 1940’s balloon observations of T, humidity and pressure began.

36. Brief History of Meteorology • High-flying military aircraft discovered the jet streams (mid- to high latitudes). • During the next decade computer programs were developed to describe the atmosphere and programs to predict the weather were developed at Princeton University. These led to the development of Numerical Weather Prediction (NWP) models used today. • The next slide is such a NWP model output analyzed by a forecaster/meteorologist.

37. http://www.ametsoc.org Fig. 5, p. 18

38. Brief History of Meteorology • In the 1960’s weather satellites were introduced. Today these provide remote sensing of many weather elements. They also provide visual and infrared observations of clouds, weather fronts and water and hurricanes. There are satellite instruments which detect ozone, and other pollution components in the atmosphere.

39. Fig. 1-13, p. 20

40. Model Output • There are many ways to observe weather models. We saw a previous slide that was a model output. • A weather map depicting ground and satellite data is also a model (called analyzed field by atmospheric scientists). • The following slide shows a simplified model of the weather by indicating air masses, high and low pressure areas, wind velocity and temperatures.

41. See Appendix B for more weather symbols and station model Fig. 1-14, p. 21

42. Weather and Climate • Weather and climate play a vital roles in the life of humans. • Weather often determines the clothing we wear and whether or not to travel. Often the balance of lives depend on weather. • Climate plays a role in determining when to plant, type of home to build and the type of construction to use (2/3 of economic activities are climate-related )

43. Fig. 1-15, p. 21

47. Fig. 1-16, p. 22

48. Fig. 1-18, p. 23

49. Fig. 1-17, p. 22