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Understanding Temperature Variations: Diurnal, Annual, Vertical, and Horizontal

Learn about the different types of temperature variations including diurnal, annual, vertical, and horizontal variations. Discover how factors like latitude, surface type, wind direction, and ocean currents affect temperature. Explore the role of temperature in weather and climate.

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Understanding Temperature Variations: Diurnal, Annual, Vertical, and Horizontal

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  1. HEAT & TEMPERATURE Part 2 Dr. Sam Miller Weather & Climate – MTDI 1200OL Plymouth State University 1

  2. Types of Temperature Variations: • Diurnal (daily): Time of day • Annual: Time of year (seasonal) • Vertical: Temperature profiles of troposphere, stratosphere, etc. • Vertical: Terrain-induced variations • Horizontal: Latitude, surface type, wind direction, ocean currents, etc.

  3. Latitude

  4. Latitude AXIS

  5. Latitude AXIS EQUATOR

  6. Latitude NORTH POLE EQUATOR SOUTH POLE

  7. Latitude 90 °N 0 °N/S 90 °S

  8. Latitude 90 °N 43 °N LATITUDE OF PLYMOUTH 0 °N/S 90 °S

  9. Latitude SUNLIGHT 90 °N 0 °N/S 90 °S

  10. Latitude SUNLIGHT 90 °N LOW LATITUDES RECEIVE DIRECT SUNLIGHT 0 °N/S 90 °S

  11. Latitude SUNLIGHT HIGH LATITUDES RECEIVE INDIRECT SUNLIGHT 90 °N 0 °N/S HIGH LATITUDES RECEIVE INDIRECT SUNLIGHT 90 °S

  12. Latitude SUNLIGHT TERRESTRIAL (IR) RADIATION

  13. Latitude BETWEEN 37 °N AND 37 °S, INCOMING SUNLIGHT IS GREATER THAN OUTGOING IR

  14. Latitude NORTH OF 37 °N, OUTGOING IR IS GREATER THAN INCOMING SUNLIGHT SOUTH OF 37 °S, OUTGOING IR IS GREATER THAN INCOMING SUNLIGHT

  15. Latitude NET LOSS 37 °N NET GAIN 37 °S NET LOSS

  16. Latitude • Between 37 °N and 37 °S, more heat is gained from sunlight than is lost via terrestrial infra-red • North of 37 °N, and south of 37 °S, more heat is lost via terrestrial infra-red than is gained from sunlight • QUESTION: Why doesn’t the temperature at the equator go to infinity? Why doesn’t the temperature at the poles go to absolute zero?

  17. Latitude • Between 37 °N and 37 °S, more heat is gained from sunlight than is lost via terrestrial infra-red • North of 37 °N, and south of 37 °S, more heat is lost via terrestrial infra-red than is gained from sunlight • ANSWER: Currents in the oceans and atmosphere redistribute excess heat away from the equator toward the poles. (Remember advection – which is horizontal convection.)

  18. Types of Temperature Variations: • Diurnal (daily): Time of day • Annual: Time of year (seasonal) • Vertical: Temperature profiles of troposphere, stratosphere, etc. • Vertical: Terrain-induced variations • Horizontal: Latitude, surface type, wind direction, ocean currents, etc.

  19. Surface Type • Land and water distribution (surface type, at station and upwind) • Ocean currents (gyres, THCB) • Other • Urban heat island • Local winds, such as sea breezes

  20. Land and Water Distribution • Land heats up and cools off about four times faster than ocean surface • Land stations experience wider diurnal and annual variations in temperature • Maritime stations or stations downwind of oceans experience narrowdiurnal and annual temperature variations

  21. CONTINENT IS UPWIND OCEAN IS UPWIND

  22. Surface Type • Land and water distribution (surface type, at station and upwind) • Ocean currents (gyres, THCB) • Other • Urban heat island • Local winds, such as sea breezes

  23. OCEAN STORES A TREMENDOUS AMOUNT OF HEAT AND HAS STRONG NORTH-SOUTH VARIATIONS IN SEA SURFACE TEMPERATURE

  24. North Atlantic Gyre Clockwise circulation of ocean water in the Atlantic Period ~= 6 months

  25. North Atlantic Gyre The Gulf Stream is part of the gyre

  26. High-resolution image of sea surface temperature COLD WATER GULF STREAM WARM WATER

  27. OCEAN CURRENTS LIKE THE GULF STREAM MOVE HEAT AROUND AND AFFECT THE AIR TEMPERATURE ABOVE THE SEA SURFACE

  28. Surface Type • Land and water distribution (surface type, at station and upwind) • Ocean currents (gyres, THCB) • Other • Urban heat island • Local winds, such as sea breezes WE WILL RETURN TO THE SUBJECT OF THERMOHALINE CONVEYOR BELT WHEN WE DISCUSS CLIMATE CHANGE

  29. Air Temperature and Human Comfort

  30. Humans perceive different temperatures depending upon atmospheric conditions • Our Internal Temperature: 98.6 °F • There is a constant heat exchange between our skin and the environment • The temperature we perceive depends on our ability to maintain our body temperature • If we gain more heat than we lose, we feel hot • If we lose more heat than we gain, we feel cold • Air temperature, wind and humidity can affect this ability

  31. Cold Weather Concerns • Wind-chill equivalent temperature • How cold the wind makes us feel, taking into account wind and temperature • Under calm conditions • Warm air layer forms next to our skin due to conduction • Once wind starts to blow • Insulating layer is swept away • Heat is rapidly removed from the skin • The faster the wind blows, the greater the heat loss, and the colder we feel

  32. Current conditions? • http://vortex.plymouth.edu Table 3-2, p.70

  33. Current conditions? • http://vortex.plymouth.edu Table 3-2, p.70

  34. Hypothermia – rapid, progressive mental and physical collapse that accompanies the lowering of human body temperature • Common when skin is wet for long periods of time • Can happen with temperatures as warm as 50’s°F

  35. What happens when the body temperature goes down? • 95°F – mild hypothermia • Shivering can increase body temperature 3.5°F • 90°F – speech slurs, motor functions fail, shivering stops • 86°F – lose consciousness • 82.4°F – heart stops

  36. Review

  37. There are four main heat transfer mechanisms in the Earth system • Radiation: Solar (visible) and Terrestrial (IR) • Conduction: Heats lowest few cm of atmosphere • Convection: Fluid motion carries heat to great heights • Horizontal convection = advection • Transport by the wind • Latent: Involves change of phase • Sublimation and deposition • Evaporation and condensation • Melting and freezing

  38. Temperature is a measure of the kinetic energy in a sample of material (like air) • There are three temperature scales • Fahrenheit • Celsius • Absolute (Kelvin) • Boiling, freezing, and absolute zero on three scales • Diurnal, annual, vertical, and horizontal variations • - Human comfort: Wind chill equivalent temperature

  39. Additional Graphics Sources http://resources.emb.gov.hk/cphysics/heat/tep/trans/kinetic_theory.gif http://earthobservatory.nasa.gov/Newsroom/NewImages/images_topic.php3?topic=oceans&img_id=5196 http://sam.ucsd.edu/sio210/gifimages/sst_brown.gif

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