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Earth’s Temperature, Concepts, and Patterns

Earth’s Temperature, Concepts, and Patterns. “The temperature of the air at any time and at any place in the atmosphere is the result of the interaction of a variety of complex factors.” — McKnight and Hess, p. 75. Global Temperatures. Temperature Concepts and Measurement  

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Earth’s Temperature, Concepts, and Patterns

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  1. Earth’s Temperature,Concepts, and Patterns “The temperature of the air at any time and at any place in the atmosphere is the result of the interaction of a variety of complex factors.” — McKnight and Hess, p. 75.

  2. Global Temperatures • Temperature Concepts and Measurement   • Principal Temperature Controls   • Earth’s Temperature Patterns  • Air Temperature and the Human Body 

  3. TEMPERATURE OF THE EARTH

  4. Measuring Temperature • An expression or a measurement of heat • Temperature Scales • Fahrenheit • Celsius • Kelvin

  5. Thermometer andInstrument Shelters

  6. Solar Energy • Electromagnetic Radiation • Oscillation of electrons • Does not require a medium (presence of matter) • Travels from Sun through great voids in space without loss of energy • Divergence from a central focus (Sun), results in intensity of solar energy, and diminishes with distance from the Sun

  7. Solar Wavelengths • Distance betweens two successive wave crests • Electromagnetic spectrum of wavelengths • Visible light • Ultraviolet radiation • Near infrared radiation

  8. Insolation Incoming solar radiation Shortwave energy Terrestrial Energy Longwave energy

  9. Solar versus Terrestrial Radiation

  10. Basic Processes in Heating and Cooling the Atmosphere Radiation All objects radiate electromagnetic energy, but hot objects radiate with greater intensity than cool objects.

  11. Basic Processes in Heating and Cooling the Atmosphere Reflection vs. Absorption An object that is a good absorber of insolation warms up rapidly (its atoms vibrate more rapidly and more easily than an object that is a good reflector)

  12. Scattering Basic Processes in Heating and Cooling the Atmosphere • Gas molecules and particulate matter deflect light waves and redirect them. • Some of the waves are backscattered to space and thus lost to Earth. • Other waves continue to Earth as diffuse energy Path length, scattering, and red sunsets

  13. Transmission Basic Processes in Heating and Cooling the Atmosphere Light passes through a medium, as when light waves pass through a clear pane of glass. Greenhouse Effect • The atmosphere easily transmits shortwave radiation from the sun • The atmosphere is a poor transmitter of long waver energy radiated from Earth’s surface

  14. Quick Review… • Conduction • Heat energy (vibration of atoms) passes from one place to another by this method • Convection • This is the movement of mass by the gain or loss of heat energy • Warming air heats, expands, & rises • Cooling air loses heat, contracts & sinks

  15. Advection This is the horizontal transfer of heat such as by wind or air masses Quick Review…

  16. Adiabatic Cooling and Warming The change in pressure and therefore the temperature of air that is rising or descending

  17. Latent Heat (of condensation) This is heat stored in the air with water vapor It is non-sensible (“hidden”) energy, as it cannot be felt It becomes heat of condensation (sensible), when the water vapor condenses and becomes liquid water droplets

  18. Diurnal (daily) temperature variability • Solar radiation maximum—when? • Temperature maximum—when? • Does this pattern look right? • Why the lag? • Right! Earth's longwave radiation

  19. Principal Temperature Controls • Latitude • Affects insolation • Temps lower towards to poles (TempofEarth.mov) • Global Insolation Patterns produce climate zones • Lower temps towards poles = more snow cover (more albedo) = even less solar radiation to warm Earth (SeasonSnowNAmGSFC2487.mpg) • Cloud Cover • High albedo • Moderate temperatures – cooler days, warmer nights • Altitude • High altitude has greater daily range • High altitude has lower annual average

  20. Effects of Latitude Latitudinal Radiation Balance

  21. Effects of Latitude

  22. Effects of Latitude • Variations in Heating by Latitude and Season • Latitudinal Differences • Angle of incidence

  23. Effects of Latitude Day Length Noontime sun

  24. Path Length Effects of Latitude

  25. More than Latitude • Examine Map: • Observations… • Higher the latitude the bigger the annual temperature range • Bigger temperature shift over the continents - watch isotherms bulge equatorward in winter and poleward in summer • Ocean currents: cold currents on west coast; warm on the east coast • Warmest temperatures are over the subtropics • WHY?

  26. Land-Water Contrasts • Causes • Transparency of water • Specific heat, Evaporation, and Mixing (movement) • Ocean currents and sea surface temperatures • Marine vs. continental effects • Observe continents and oceans in: TempChangeGlobe.mov • Land heats up more (and faster) than water and takes longer to cool down

  27. Land Is Opaque

  28. Land–Water Heating Differences  

  29. Cloud Development • Clouds and location of clouds reduce range (lower highs; higher lows) • This movie of UV radiation received at surface shows much less off west coast of North America during summer: UV_USAGSFC2197.mpg

  30. Atmospheric Obstruction Effects of Cloud Cover Clouds and haze hinder insolation

  31. Effects of Altitude

  32. Effects of Altitude • ENVIRONMENTAL LAPSE RATE (ELR) • Cooler temperatures at higher elevations • Look at mountains in this North American movie: TempChNorAmGSFC2567.mpg • Focus on mountains in this world movie: GlobTempGSFC1017.mpg

  33. Other Factors Oft-asked • Do NOT show up on general maps • Urban heat island • Forest fires burning • Wind chill (WindChillMovie.mov) • Anomalies (European heat wave of summer '03) • Heat index

  34. Earth’s Temperature Patterns • January Temperature Map   • Thermal equator movement southward • More movement over large continents • July Temperature Map   • Thermal equator movement northward • More movement over large continents • Annual Range of Temperatures • Continentality: the interior remoteness from the sea

  35. January Temperatures

  36. July Temperatures

  37. Global Temperature Ranges

  38. Air Temperature and the Human Body • Wind chill • Correlates cold and wind speed • Heat index • Correlates heat and humidity

  39. Wind Chill Table

  40. Heat Index Table

  41. Quick Review • Highest Temperatures in High Sun in Subtropics • In Winter, get stronger temperature gradient from poles to equator • Isotherms bend equatorward over land in winter (warmer oceans) • Heat Equator expands over land • Isotherms bend before hit land, esp. West Coast of continents • Annual Temperature Range of Land vs. Ocean

  42. Can you Guess… • Where in the western hemisphere would it be warmest? Quito; Panama City; Atlanta; Toronto • Staying at about the same latitude, what place has the least extreme climate? San Francisco; St. Louis; Norfolk

  43. Weather vs. ClimateWhat’s The Difference? • Weather: The state of the Atmosphere at any given moment • “What you get” • Climate: The average state of the atmosphere over a long period of time • “What you expect”

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