1 / 43

Introduction to the Atmosphere

Introduction to the Atmosphere . Lutgens & Tarbuk “The Atmosphere” chp1 CollegeNow Meteorology 31 March 11 2008. http://www.globalsecurity.org/wmd/library/policy/army/fm/3-6/3-6apc.htm. Elements of climate and weather. Elements. Measurements. Air temperature Humidity

ilyssa
Télécharger la présentation

Introduction to the Atmosphere

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. Introduction to the Atmosphere Lutgens & Tarbuk “The Atmosphere” chp1 CollegeNow Meteorology 31 March 11 2008 http://www.globalsecurity.org/wmd/library/policy/army/fm/3-6/3-6apc.htm

  2. Elements of climate and weather Elements Measurements • Air temperature • Humidity • Type & amount of cloudiness • Type &a mount of precipitation • Pressure exerted by air • Wind speed and direction • Thermometers • Barometers • Pschycrometers • Radiosondes • Balloons • Stations • Satellites • Rockets • Planes • Buoys

  3. The Structure of the Atmosphere Layers of gases that extent into space. Variations in temperature, humidity, pressure, and composition. Components include water vapour, ozone, aerosols, Nitrogen, Oxygen, Ar, CO2, and other gases. Troposphere Stratosphere Mesosphere Thermosphere

  4. The Structure of the Atmosphere Temperature varies vertically throughout the atmosphere

  5. The Structure of the Atmosphere Temperature variation is used to define the different layers of the atmosphere Troposphere Stratosphere Mesosphere Thermosphere The upper end of a layer is a ‘pause’, thus there is a tropopause , a stratopause, etc. These are zones where temperature is invariant.

  6. The Structure of the Atmosphere Temperature variation is used to define the different layers of the atmosphere Troposphere Stratosphere Mesosphere Thermosphere The upper end of a layer is a ‘pause’, thus there is a tropopause , a stratopause, etc. These are zones where temperature is invariant. After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25

  7. The Structure of the Atmosphere Some phenomena are correlated with specific layers of the atmosphere Troposphere: Layer of mixing of gases, also the Sphere of Weather Stratosphere: Residence of Ozone layer Thermosphere: Site of Aurorae After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25

  8. What causes vertical variation in Temperature?

  9. What causes vertical variation in Temperature? Temperature is decreasing with height, the further away from the warm, radiating surface of the earth, the lower the temperature of the air mass. In the Troposphere, for every kilometer of increase in altitude, there is a 6.5°C drop in temperature (called the “normal lapse rate)

  10. But Temperature increases Temperature increases in a few layers of the atmosphere. What layers? Image after: http://wpos12.physik.uni-wuppertal.de

  11. But Temperature increases Temperature increases in a few layers of the atmosphere. What layers? Stratosphere Thermosphere Image after: http://wpos12.physik.uni-wuppertal.de

  12. But Temperature increases Temperature increases in a few layers of the atmosphere. What layers? Stratosphere Thermosphere Temperature increases for different reasons in the two spheres. Image after: http://wpos12.physik.uni-wuppertal.de

  13. Stratosphere Temperature increase The air mass needs to receive heat in order to be wamed. Closer to the earth’s surface, it is the heat that is radiating from the earth that warms the air. In the stratosphere, the energy to heat the air comes chemical reactions, ultimately through UV radiation, in the ozone-oxygen cycle Image after: http://wpos12.physik.uni-wuppertal.de

  14. Stratosphere Temperature increase Step 1 The air mass needs to receive heat in order to be wamed. Closer to the earth’s surface, it is the heat that is radiating from the earth that warms the air. In the stratosphere, the energy to heat the air comes chemical reactions, ultimately through UV radiation. Ozone is present in high concentrations in the stratosphere. It is created and destroyed in the ozone-oxygen cycle. Step 2 Image after: http://science.howstuffworks.com/earth5.htm

  15. Stratosphere Temperature increase Step 1: Oxygen Molecule absorbs UV light and splits The air mass needs to receive heat in order to be wamed. Closer to the earth’s surface, it is the heat that is radiating from the earth that warms the air. In the stratosphere, the energy to heat the air comes chemical reactions, ultimately through UV radiation, in the ozone-oxygen cycle Step 2: Oxygen atom reacts with molecular oxygen creating ozone Image after: http://science.howstuffworks.com/earth5.htm

  16. Stratosphere Temperature increase Step 1: Oxygen Molecule absorbs UV light and splits The air mass needs to receive heat in order to be wamed. Closer to the earth’s surface, it is the heat that is radiating from the earth that warms the air. In the stratosphere, the energy to heat the air comes chemical reactions, ultimately through UV radiation, in the ozone-oxygen cycle Step 2: Oxygen atom reacts with molecular oxygen creating ozone When Step 2 is run backwards, Ozone absorbs UV radiation, splits into molecular and atomic oxygen, and heat is added to the stratosphere Image after: http://science.howstuffworks.com/earth5.htm

  17. Ever hear of Ozone Depletion? The Ozone molecule, as we have seen, is absording solar radiation. The Ozone layer is created by the sun, and it protects the earth beneath it from the sun. It is the result of a chemical process. Like any other chemical process, it can be interfered with. Chlorofluorocarbons can react with ozone in the atmosphere, and prevent the formation of ozone. Image after: http://www.safety-devices.com/what_is_ozone.htm

  18. Ever hear of Ozone Depletion? Chlorine and Ozone react CFCs are normally stable compounds. They get into the air, are pushed up into the stratosphere by wind currents, and there are exposed to UV rays. The UV rays break the bonds that hold the CFCs together, releasing free Chlorine. That cholorine reacts with ozone, stripping off one of its oxygens. Other free oxygen in the atmosphere can react with the Chloro-oxide, creating molecular oxygen, leaving the Chlorine free to rip apart other ozone molecules. Chlorine is liberated to react again with Ozone Image after: http://www.safety-devices.com/what_is_ozone.htm

  19. Ever hear of Ozone Depletion? Chlorine and Ozone react Chlorine is liberated to react again with Ozone CFCs can destroy ozone molecules, this competes again the action of UV rays creating ozone. Image after: http://www.safety-devices.com/what_is_ozone.htm

  20. The Ozone “Hole” Image after: http://www.theozonehole.com

  21. The Ozone “Hole” Image after: http://www.theozonehole.com

  22. What about the Thermosphere temperature increase? So we can explain the temperature increase in the stratosphere as a result of energy input from the sun. In the Thermosphere, there is a similar effect. Oxygen and Nitrogen in the layer are bombarded by high energy solar radiation (short wave, think like how ‘microwaves’ can heat things). This causes an increase in temperature within the Thermosphere. To what temps? After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25

  23. What about the Thermosphere temperature increase? To what temps? Here we see up to 50°C, but temperatures actually get up to 1,ooo°C After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25

  24. What about the Thermosphere temperature increase? Up to 1,ooo°C However: HEAT IS NOT THE SAME AS TEMPERATURE After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25

  25. Heat is not the Same as Temperature Temperature: A statistical property of objects, a measure of the movement of its component molecules. Fast moving particles mean an object has a high temperature. Heat: A measure of energy So what does that mean about the Thermosphere????

  26. Heat is not the Same as Temperature Temperature: A statistical property of objects, a measure of the movement of its component molecules. Fast moving particles mean an object has a high temperature. Heat: A measure of energy So what does that mean about the Thermosphere???? The air molecules are very ,very fast moving. A sample of it has low heat energy. If an astronaut put their hand out into the thermosphere, it sure wouldn’t feel hot.

  27. Variation in vertical Structure What is the altitude of the Tropopause? 10 km? After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25

  28. Variation in vertical Structure Tropopause position varies with latitude. At the Poles, it can be as shallow as 8 km. This is because air at the poles is in fact sinking. At the equator, it can reside at an altitude of 18 km. This is because the warm, moist air of the equator is rising through the atmosphere. In the Middle Latitudes, the Tropopause is higher in the summer and lower in the winter. After: http://www.csulb.edu/~rodrigue/geog140/lectures/thermalstructure.html

  29. So…. The atmosphere is divided into layers on the basis of temperature, the Troposphere, the Stratosphere, the Mesosphere, and the Thermosphere. The Troposphere is where most weather and clouds occur. Normally, the further away from the surface of the earth, the cooler the air. But in the Stratosphere, the absorption of UV radiation by the ozone layer heats up the Stratosphere. And in the Thermosphere, absorption of shortwave radiation by Oxygen and Nitrogen molecules heat the Thermosphere. After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25

  30. Variations other than Temperature We can also divide the atmosphere into layers based air composition.

  31. Homosphere: Zone within which the ratio of components (Oxygen, Nitrogen, CO2, etc) does not vary much. Up to 80 km Heterosphere: Zone within which the ratio of components varies greatly. The lowermost layer is dominated by N2, then a layer of atomic Oxygen, then a layer dominated by Helium (He), and then the highest layer, dominated by atomic Hydrogen (H). Notice, the heaviest elements are lowest, and the lightest elements ‘float’ in a layer above that. Earth actually looses H and He to space at the outer edge of this sphere, gravity is insufficient to hold those gases to Earth. Also, the density of gases becomes extremely low in this layer. Said to occur from 80-10,000 km Variations other than Temperature

  32. Ionosphere: Region where N2 and Oxygen atoms are ionized; high energy rays strip off some of their electrons (iow, they become Ions). b/t 80-400 km D & E Layer: Ephemeral. At night, when there is no influx of solar radiation, the ions disappear, reappearing during daylight F Layer: Constant, but very weak. Low density of atoms and molecules prevents ions from disappearing, so they last throughout the night. Variations other than Temperature Aurora: borealis and australis Interaction between electromagnetic ‘solar wind’ and the earth’s magnetic field. The solar particles are directed to the poles, where they interact with molecules in the atmosphere, energizing them, creating lights.

  33. Aerosols: Particulate matter suspended in the atmosphere, smoke, dust, etc. Variations other than Temperature After: http://namma.nsstc.nasa.gov/reporting/large/

  34. Atmospheric Structure After: http://www.csulb.edu/~rodrigue/geog140/lectures/thermalstructure.html

  35. Atmospheric Structure After: http://www.csulb.edu/~rodrigue/geog140/lectures/thermalstructure.html

  36. Titan’s Atmosphere Earth’s atmosphere is not, clearly, the same as other planets, neither in composition nor strucuture.

  37. Jupiter’s Atmosphere Earth’s atmosphere is not, clearly, the same as other planets, neither in composition nor strucuture. After: http://cseligman.com/text/planets/jupiteratmostruct.jpg

  38. Jupiter’s Atmosphere Jupiter has Aurora also, however they result from interactions between Jupiter’s magnetic field and its moons. This is a UV image. After: http://cseligman.com/text/planets/jupiteratmostruct.jpg

  39. Jupiter’s Atmosphere Jupiter, and other planets, have weather. But it is wildly different than on earth. The Great Red Spot is a storm that has been observed ever since Jupiter has been telescopically observed (iow, +300 years), and is as big as the entire surface area of the earth. The smaller red spot below it has a diameter as large as that of earth. The red storms are thought to have stirred up material from deeper within jupiter, while the white storms aren’t strong enough to reach below its atmosphere. Notice the banding of the atmosphere in this image, this is ‘zonal banding’, it occurs on earth too. After: http://cseligman.com/text/planets/jupiteratmostruct.jpg

  40. Atmospheric Circulation Cells: Convecting cells of rising and sinking air that carry moisture and heat with them across earth More on structure: Afterhttp://www.climateprediction.net/science/cl-intro.php

  41. Atmospheric Circulation Cells: Convecting cells of rising and sinking air that carry moisture and heat with them across earth More on structure: Afterhttp://www.climateprediction.net/science/cl-intro.php

  42. Atmospheric Circulation Cells: Convecting cells of rising and sinking air that carry moisture and heat with them across earth More on structure: Afterhttp://www.climateprediction.net/science/cl-intro.php

  43. Keep in Mind So… The altitudes at which the boundaries for the layers (the pauses) occur is not the same throughout the world. There is variation in all directions. The rate of temperature change is not the same within the layers throughout the world, it varies too, largely with changes in latitude. In fact, all characteristics can vary between different locations on the earth, with respect to latitude and longitude. We will find that latitudinal variation is often related to Insolation. The atmosphere can be divided into four layers based on temperature, the Troposphere, Stratosphere, Mesosphere, and Thermosphere. There is vertical variation of temperature within those layers, and you can explain that variation The atmosphere can also be divided into layers based on their composition, such as the Homosphere and Heterosphere or the Ionosphere Some components, like Ozone, can have their atmospheric concentrations changed by biological activities (human or otherwise)

More Related