1 / 26

Weather

Weather. A study in Variables. What is meteorology?. Meteorology is the study of current atmospheric conditions. Very simplified definition! Includes the sciences of chemistry & physics. Can include climatology, ecology, & oceanography.

sheba
Télécharger la présentation

Weather

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. Weather A study in Variables

  2. What is meteorology? • Meteorology is the study of current atmospheric conditions. • Very simplified definition! • Includes the sciences of chemistry & physics. • Can include climatology, ecology, & oceanography. • Goals include understanding, predicting, and artificial control of phenomena of the atmosphere.

  3. Why isn’t the meteorologist always right? • Weather consists of MANY related variables. These include: • Air pressure • Atmosphere structure • Water and water vapor • Energy and heat (a.k.a. temperature) • Wind and air currents • Global rotation and effects on wind

  4. Weather Forecasting = 4 pieces • Observations • Data collection • Radar • Satellites • Weather stations • Computer Models • Many! • Up to the meteorologist to choose • Farther out in time = less reliable. • Audience interpretation

  5. What makes weather happen? • Variables! They all interact to make the weather, and they are all related. • We will look at the role each variable plays in creating our weather. • Different variable each week. • This week focus on atmosphere, energy/heat.

  6. Weather information • Weather information focus will be in form of maps • Information on the map is generated from weather stations. • Weather stations report on their local conditions. • This information is compiled into the weather map. • Large group focus will be on each variable (information represented by stations), small groups will be supporting labs and activities.

  7. Weather Stations • Report on local conditions • Almost completely automated • Observe: Temperature, humidity, air pressure, wind speed and direction, cloud cover and height, visibility and weather (rain, snow, fog)

  8. Variable: Atmosphere - composition • 78% Nitrogen • 21% Oxygen • .93% Argon • Remainder are trace gases, dust, pollution. • .039% Carbon dioxide (major greenhouse gas) • Water varies with temperature, also important for storing and releasing heat energy (latent heat). • Dust and pollutants vary with location.

  9. Variable: Atmosphere - Structure • Consists of four major layers (top to bottom) • Thermosphere • Mesosphere • Stratosphere • Troposphere • Mnemonic: Too Many Stupid Tests • Separated by a “-pause” • Tropopause, stratopause, mesopause • Space is the “exosphere”, transition = “ionosphere”

  10. Atmosphere structure (pg 480)

  11. Troposphere • 0-10 Km (Mt. Everest peak is above the troposphere) • Temperature decreases with height. • Earth radiates heat so air is warmer closer to the ground. (mountains) • Pressure decreases with height.(airplanes) • Layer of the atmosphere we live in. • Top boundary is the tropopause. • Jet stream located here. • Lid of the weather.

  12. Stratosphere • 10-50 Km • Pressure decreases with height. • Air temperature increases with height. • Ozone layer located here. • Absorbs UV causing the rise in temperature. • Commercial airplanes fly here (bottom). • Supersonic airplanes fly here (top). • Top boundary is the stratopause.

  13. Mesosphere • Pressure decreases with height. • Pressure is so low that blood would boil at normal body temperatures. • Temperature decreases with height. • Little/No ozone to absorb UV • 50-85 Km • Visible meteors (shooting stars) occur here. (friction) • Top boundary is the mesopause.

  14. Thermosphere • Pressure decreases with height. • Temperature increases with height. • Few molecules present • If energy is absorbed, it will result in a large temperature increase. • Molecules moving FAST. • Aurora borealis located here and beyond. • Lights due to solar winds interacting with Earth’s magnetic field.

  15. Variable: Heat Energy • Heat is a measure of how much molecules are moving. • Three main forms of heat energy transfer in the atmosphere. • Conduction- molecules crash together to transfer heat energy. • Convection- the transfer of heat by mixing or circulation. • Radiation- the transfer of energy by electromagnetic waves (EM). • Heat flow ALWAYS from high to low temperature matter

  16. Conduction-molecules touching • Substances conduct heat differently – metal is a good conductor • Air is very poor conductor • For atmosphere – conduction not so important

  17. Convection - molecules mixing • Lots of heat transferred in atmosphere by convection • Happens in fluids like the ocean and air where atoms and molecules are free to move • Hot stuff rises, cold stuff sinks.

  18. Radiation - EM waves • Does not need molecules in order to transfer heat like convection and conduction. • Can travel through outer space. • All objects emit radiant energy. (Night vision goggles/cameras) • Hotter objects emit more energy (shorter wavelengths) than cooler objects. • Objects that are good absorbers are also good emitters.

  19. So What? • Earth gets ALL of its incoming energy by radiation from the sun. • 30% of incoming solar radiation is reflected and scattered. (Does nothing for Earth.) • (20% reflected from clouds, 5% reflected from sea/ice/sand, 5% reflected from atmosphere.) • 20% of incoming solar radiation is absorbed by the atmosphere and clouds. • 50% of incoming solar radiation is absorbed at the surface.

  20. Incoming radiation (pg 486)

  21. Effects on the atmosphere. • The atmosphere gains energy from the sun. • The Earth gains energy from the sun and Earth also radiates heat into the atmosphere. • The greenhouse gases (water & CO2) in the atmosphere trap the heat radiated by the Earth. • So, the atmosphere is a sandwich!

  22. Sun Atmosphere Earth The atmosphere is a sandwich? • Heated from above by the sun. • Heated from below by the Earth. • Atmosphere is the hamburger, and the heat sources are the buns!

  23. The REAL sandwich (not in book)

  24. Earth is heated unevenly • Land and water heat differently. • Water has a high specific heat (amount of energy needed to raise temperature). • It acts like an energy sponge. It will soak up or release energy without changing temperature(latent/hidden heat). • Water won’t heat or cool as fast as land. • Water won’t reach the temperature extremes that land will. • Land close to large bodies of water will be more moderate. • Higher elevations are cooler. • Global location/latitude makes a difference.

  25. Earth Temperature Distribution

  26. Uneven heating has effects. • Causes differences in pressure and winds that we will discuss in the coming weeks.

More Related