Meteorology

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Meteorology

  1. 1. “ Atmosphere”
  2. 2. Vocabulary <ul><li>Ozone </li></ul><ul><li>Troposphere </li></ul><ul><li>Stratosphere </li></ul><ul><li>Mesosphere </li></ul><ul><li>Thermosphere </li></ul><ul><li>Exosphere </li></ul><ul><li>Radiation </li></ul><ul><li>Conduction </li></ul><ul><li>Convection </li></ul>
  3. 3. Atmospheric Basics <ul><li>Climate and weather relies in how solar energy interacts with the atmosphere, and how the interactions combine to produce weather and climate </li></ul>
  4. 4. Atmospheric Composition <ul><li>Air is a combination of many gases, each with its own unique characteristics </li></ul><ul><li>These gases form Earth’s atmosphere, which extends from Earth’s surface to outer space </li></ul>
  5. 5. <ul><li>About 99% of the atmosphere is composed of nitrogen and oxygen </li></ul><ul><li>These main components are critical for life on Earth </li></ul><ul><li>If either were to change significantly, life as we know it could not exist. </li></ul>
  6. 6. Key Atmospheric Gases <ul><li>The amount of water vapor in the atmosphere at any given time or place changes constantly, from 4% to 0% </li></ul><ul><li>Percentage varies with seasons, altitude, and with the surface features beneath the air </li></ul>
  7. 7. <ul><li>Water vapor, the gaseous form of water, is the source of clouds, rain, and snow. </li></ul><ul><li>Water is the only substance in the atmosphere that exists in all three states </li></ul><ul><li>When water changes state to another, heat is either absorbed or released, this heat greatly affects motions that create weather and climate. </li></ul>
  8. 8. <ul><li>Atmosphere also contains solids such as dust and salt from the wind and oceans </li></ul><ul><li>Dust and salt play a role in cloud formation </li></ul><ul><li>Ice is the third solid found the atmosphere as hail and snow </li></ul>
  9. 9. Ozone <ul><li>Ozone is a gas formed by the addition of a third oxygen atom to an oxygen molecule. </li></ul><ul><li>Absorbs ultraviolet radiation </li></ul><ul><li>It is thinning </li></ul>
  10. 10. Structure of the Atmosphere <ul><li>Made up of several different layers </li></ul><ul><li>Each layer differs in composition and temperature </li></ul><ul><li>There are lower atmospheric layers and upper atmospheric layers </li></ul>
  11. 11. Lower Atmosphere Layers <ul><li>Layer closest to the Earth’s surface, the troposphere, contains most of the mass of the atmosphere, including water vapor </li></ul><ul><li>Most weather takes place here </li></ul><ul><li>Most pollution is collected </li></ul><ul><li>General temp decrease from bottom to top </li></ul><ul><li>Upper limit is called the tropopause, 9km </li></ul>
  12. 12. <ul><li>The next layer up is the stratosphere, made up primarily of concentrated ozone </li></ul><ul><li>Ozone absorbs more radiation than the troposphere. </li></ul><ul><li>Stratosphere is heated </li></ul><ul><li>Gradual increase in temp </li></ul><ul><li>Top layer called a stratopause, 50km up </li></ul>
  13. 13. Upper Atmosphere <ul><li>Above the stratopause is the mesosphere </li></ul><ul><li>No concentrated ozone </li></ul><ul><li>Temp decreases </li></ul><ul><li>Mesopause is the top layer </li></ul>
  14. 14. <ul><li>Above the mesopause is the thermosphere. </li></ul><ul><li>Only minute portion of atmosphere’s mass </li></ul><ul><li>This layer increases in temperature, more than 1000°C </li></ul>
  15. 15. <ul><li>Ionosphere is part of the thermosphere </li></ul><ul><li>Made up of electrically charged particles of progressively lighter gases </li></ul><ul><li>Exosphere is the outermost layer of Earth’s atmosphere </li></ul><ul><li>Light gases such as helium and hydrogen are found in this layer </li></ul><ul><li>There is no clear line between the exosphere and space </li></ul>
  16. 16. Solar Fundamentals <ul><li>The sun is the source of all energy in the atmosphere. </li></ul><ul><li>This energy is transferred to Earth and throughout the atmosphere in three ways </li></ul>
  17. 17. Radiation <ul><li>Radiation is the transfer of energy through space by visible light, ultraviolet radiation, and other forms of electromagnetic waves. </li></ul><ul><li>While Earth is absorbing solar radiation, it is also continuously sending energy back into space. </li></ul><ul><li>35% of incoming radiation is deflected </li></ul><ul><li>15% is absorbed be the atmosphere </li></ul>
  18. 18. <ul><li>Rate of absorption for any particular area varies depending on the physical characteristics of the area and the amount of solar radiation it absorbs </li></ul><ul><li>Water heats up and cools down more slowly than land. </li></ul><ul><li>Darker objects absorb energy faster than lighter ones </li></ul>
  19. 19. <ul><li>Solar radiation does not heat air directly </li></ul><ul><li>Most radiation travels as short wavelengths and the atmosphere does not easily absorb short wavelengths and so is absorbed by the Earth’s surface. </li></ul>
  20. 20. <ul><li>The energy then released in the heat of the Earth’s surface gives off long wavelengths </li></ul><ul><li>It is absorbed by the atmosphere and warms the air through the processes of conduction and convection </li></ul>
  21. 21. Conduction <ul><li>Conduction which is the transfer of energy that occurs when molecules collide </li></ul><ul><li>Like a pot of boiling water </li></ul><ul><li>For conduction to occur, substances must be in contact with one another </li></ul><ul><li>Conduction affects only a very thin atmospheric layer </li></ul>
  22. 22. Convection <ul><li>Convection - transfer of energy by the flow of a heated substance </li></ul><ul><li>Pockets of air near the Earth’s surface are heated, become less dense than the surrounding air, and rise </li></ul><ul><li>As the warm air rises, it expands and starts to cool </li></ul><ul><li>When it cools below the temp of the surrounding air, it increases in density and sinks </li></ul>
  23. 23. <ul><li>It heats again and the cycle continues </li></ul><ul><li>Convection currents are among the main mechanisms responsible for the vertical motions of air, which in turn cause the different types of weather </li></ul>
  24. 24. “ State of the Atmosphere”
  25. 25. Vocabulary <ul><li>Temperature </li></ul><ul><li>Heat </li></ul><ul><li>Dew point </li></ul><ul><li>Condensation </li></ul><ul><li>Lifted condensation level </li></ul><ul><li>Temperature inversion </li></ul><ul><li>Humidity </li></ul><ul><li>Relative humidity </li></ul>
  26. 26. Temperature Versus Heat <ul><li>Heat and temperature are two different concepts. </li></ul><ul><li>Temperature is a measurement of how rapidly or slowly molecules move around. </li></ul><ul><li>Heat, on the other hand, is the transfer of energy that occurs because of a difference in temperature between substances. </li></ul>
  27. 27. <ul><li>Direction of heat flow depends on temperature </li></ul><ul><li>Heat flows from an object of higher temperature to an object of lower temperature </li></ul><ul><li>Heat is the transfer of energy that fuels atmospheric processes, while temperature is used to measure and interpret that energy </li></ul>
  28. 28. Measuring Temperature <ul><li>Three units of measuring temp </li></ul><ul><ul><li>Fahrenheit (F) </li></ul></ul><ul><ul><li>Celsius (C) </li></ul></ul><ul><ul><li>Kelvin (K) </li></ul></ul><ul><ul><ul><li>Is based on absolute zero which corresponds to about -273 C </li></ul></ul></ul><ul><ul><ul><li>More direct measure of molecular activity, because at absolute zero, molecular motion theoretically stops (no negative numbers) </li></ul></ul></ul>
  29. 29. Dew Point <ul><li>The dew point is the temperature to which air must be cooled at constant pressure to reach saturation. </li></ul><ul><li>Dew point is important because until air is saturated, condensation can not occur </li></ul>
  30. 30. <ul><li>Condensation occurs when matter changes state from a gas to a liquid. </li></ul><ul><li>Dew point is often called the condensation temperature. </li></ul>
  31. 31. Vertical Temperature Changes <ul><li>The temperature on a mountaintop is cooler than at lower elevations because the temperature of the lower atmosphere decreases with increasing distance from its heat source </li></ul><ul><li>The height at which condensation occurs is called the lifted condensation level (LCL). </li></ul>
  32. 32. <ul><li>Height of the LCL often corresponds to the base of clouds. </li></ul><ul><li>Above the LCL air becomes saturated and cools slowly </li></ul><ul><li>The rate at which saturated air cools is called the moist adiabatic lapse rate. </li></ul>
  33. 33. Air Pressure and Density <ul><li>The gravitational attraction between Earth and atmospheric gases causes particles of gas to be pulled toward the center of the Earth. </li></ul><ul><li>Atmospheric pressure decreases with height because there are fewer and fewer gas particles exerting pressure. </li></ul>
  34. 34. Pressure-Temperature-Density <ul><li>Temperature is directly proportional to pressure </li></ul><ul><li>As temperature increases or decreases pressure does the same </li></ul><ul><li>Temperature and density are inversely proportional </li></ul><ul><li>As temperature decreases, density increases. </li></ul>
  35. 35. Pressure-Temperature-Density <ul><li>As temp increases, pressure increases </li></ul><ul><li>As temperature decreases, pressure decreases </li></ul><ul><li>As temperature decreases, density increases </li></ul><ul><li>As temperature increases, density decreases </li></ul>

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