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WIND AND OCEAN CIRCULATION Continent/ Ocean contrasts Land/Sea Breeze Wind Circulation PowerPoint Presentation
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WIND AND OCEAN CIRCULATION Continent/ Ocean contrasts Land/Sea Breeze Wind Circulation

WIND AND OCEAN CIRCULATION Continent/ Ocean contrasts Land/Sea Breeze Wind Circulation

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WIND AND OCEAN CIRCULATION Continent/ Ocean contrasts Land/Sea Breeze Wind Circulation

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  1. WIND AND OCEAN CIRCULATION Continent/ Ocean contrasts Land/Sea Breeze Wind Circulation Ocean Currents

  2. DIFFERENCES IN OCEANIC AND CONTINENTAL THERMAL PROPERTIES Land heats & cools more rapidly than oceans. This is why: Specific Heat = heat energy required to increase the temperature (1 K) of an amount of substance (1 g or Kg.) Water: 4,200 joules.gr-1.K-1(4.2 J.Kg-1.K-1) Soil (land): 2500 joules.gr-1.K-1(0.80 J.Kg-1.K-1) More energy is required to warm/cool water (high specific heat) than soil (land). • p. 45

  3. SPECIFICIC HEAT: Water molecule + + H H O -

  4. SPECIFICIC HEAT: Water molecule + + H H O - Hydrogen bonds - - + +

  5. SPECIFICIC HEAT: Water molecule + + 20,000 KJ H H O - Hydrogen bonds - - + +

  6. SPECIFICIC HEAT: Water molecule + + 20,000 KJ H H O - Hydrogen bonds 1Kg H2O 1Kg soil Water Soil - - + +

  7. SPECIFICIC HEAT: Water molecule + + 20,000 KJ H H O - Specific heat: 4200 KJ Kg-1 °K-1 2500 KJ Kg-1 °K-1 Hydrogen bonds 1Kg H2O 1Kg soil Water Soil - - + +

  8. SPECIFICIC HEAT: Water molecule + + 20,000 KJ H H O - Specific heat: 4200 KJ Kg-1 °K-1 2500 KJ Kg-1 °K-1 Hydrogen bonds 1Kg H2O 1Kg soil Water Soil - - 20,000 4,200 + + T↑~5°K

  9. SPECIFICIC HEAT: Water molecule + + 20,000 KJ H H O - Specific heat: 4200 KJ Kg-1 °K-1 2500 KJ Kg-1 °K-1 Hydrogen bonds 1Kg H2O 1Kg soil Water Soil 20,000 2,500 - - T↑~5°K + + T↑8°K

  10. Latent Heat • more evaporation occurs on water surfaces •  more energy is used as Latent Heat (i.e.) delays the warm up of the water/ocean temperature • - p. 32 (540 cal/gram) • Lower evaporation occurs on soils • - not much latent heat used  land warms up faster. You can experience the cooling effects of evaporation when you come out of a swimming pool. You feel cold. This is caused by the water on your skin taking energy from your body to evaporate (you eventually dry out) • p. 45

  11. LATENT HEAT FLUX: Sensible Heat Sensible Heat SINKS OF INSOLATION Latent Heat Latent Heat Ground Heat Ground Heat Continents Oceans

  12. LATENT HEAT FLUX: More water available to change the state of over oceans than continents. Thus proportion to Latent Heat Flux is higher Sensible Heat Sensible Heat Latent Heat Latent Heat Ground Heat Ground Heat Continents Oceans

  13. LATENT HEAT FLUX: If a higher proportion of the available insolation is diverted to Latent Heat, then a lower proportion is available for Ground and Sensible Heat Sensible Heat Sensible Heat Latent Heat Latent Heat Ground Heat Ground Heat Continents Oceans

  14. LATENT HEAT FLUX: If a higher proportion of the available insolation is diverted to Latent Heat, then a lower proportion is available for Ground and Sensible Heat Equal Sensible Heat Sensible Heat Latent Heat Latent Heat Ground Heat Ground Heat Continents Oceans No changes in temperatures Changes in surface and air temperatures

  15. Oceans Land Penetration of Radiation Radiation penetrates through the ocean/water: Transparent Radiation does not penetrates land (energy can’t go down further): Opaque Energy is transmitted deeper into the water Energy is absorbed near the surface • p. 45

  16. Assume equal Ground Heat Flux PENETRATION OF RADIATION: Greater depth of penetration in the liquid ocean compared to solid continents Oceans Continents OCEAN CONTINENT Depth Depth Liquid Solid

  17. PENETRATION OF RADIATION: Equal quantities of energy represent equal areas “heated”. Oceans “deep” but “cool surface” – Continents “Shallow”, but “warm surface” Oceans Continents OCEAN CONTINENT Cool Warm Equal Areas Depth Depth Liquid Solid Temperature Temperature

  18. Mixing Warm water surface layer can mix with cooler water below. No such mixing occurs on land  land heats up faster. • p. 45

  19. MIXING: Calm Least Dense Warm Stable Profile – little mixing. Cooler Denser Coolest Most Dense

  20. MIXING: Calm Rough Warm Wave Energy – surface mixing. Cooler Coolest

  21. Global Wind Speeds 28 m.p.h

  22. Global Wind Speeds Rising

  23. Global Wind Speeds Falling Rising Falling

  24. Global Wind Speeds TRADE WINDS

  25. Global Wind Speeds RISING BUT TURBULENT 28 m.p.h

  26. Global Wind Speeds Ocean-Continent Contrast in North RISING BUT TURBULENT “Roaring Forties” “Furious Fifties” “Screaming Sixties” 28 m.p.h

  27. MIXING: Calm Salty Rough Saline Waters – more dense, promote vertical mixing. Warm Cooler Coolest

  28. Global Surface Salinity Warm Rising Equatorial Air Rain

  29. Global Surface Salinity Cool descending Air. Deserts.

  30. Global Surface Salinity Ice melting Most ice formation on land

  31. MIXING: Calm Salty Rough Cold Cool surface waters – (ice melting) more dense, promote vertical mixing. Warm Cooler Coolest

  32. MIXING: Calm Salty Rough Cold Cool surface waters – (ice melting) more dense, promote vertical mixing. Warm Cooler Coolest No equivalent processes within the continental surfaces.

  33. No Mixing 2 3 4 1 Lands heat and cool faster than oceans

  34. LOCAL WINDS (LAND/SEA BREEZE) Breeze = a type of daily thermal circulation system developed at the interface land-ocean. Atmospheric pressure gradient is produced by the dissimilar heating and cooling characteristics of land and water, - causes local air to flow differently during days and nights.

  35. SEA BREEZE Day: - warm air rises over land  moves to the ocean - surface winds over the oceans bring cool air to the land (H to L) Daytime development of sea breeze

  36. LAND BREEZE Night: - Land surface cools faster (H)  move to the ocean - Oceans warms up faster and became a warm low center. Night time development of land breeze.

  37. THE STORY SO FAR! • Differences in Specific Heat. • Differences in Latent Heat Flux. • Differences in the Penetration of Radiation. • Differences in Mixing. In a zone or time of EXCESS ENERGY, Oceans warm up more slowly that continents (continents warm faster). In a zone or time of DEFICIT ENERGY, Oceans cool down more slowly that continents (continents cool down faster).

  38. CAN WE BRING THIS ALL TOGETHER TO EXPLAIN PATTERNS OF GLOBAL CLIMATE?

  39. CAN WE BRING THIS ALL TOGETHER TO EXPLAIN PATTERNS OF GLOBAL CLIMATE? Oceans/Continents

  40. CAN WE BRING THIS ALL TOGETHER TO EXPLAIN PATTERNS OF GLOBAL CLIMATE? Oceans/Continents Surplus/Deficit Energy

  41. CAN WE BRING THIS ALL TOGETHER TO EXPLAIN PATTERNS OF GLOBAL CLIMATE? Oceans/Continents Surplus/Deficit Energy Global Pressure Belts

  42. CAN WE BRING THIS ALL TOGETHER TO EXPLAIN PATTERNS OF GLOBAL CLIMATE? Oceans/Continents Surplus/Deficit Energy Global Pressure Belts Pressure Gradients

  43. CAN WE BRING THIS ALL TOGETHER TO EXPLAIN PATTERNS OF GLOBAL CLIMATE? Oceans/Continents Surplus/Deficit Energy Global Pressure Belts Pressure Gradients Coriolis Effect

  44. CAN WE BRING THIS ALL TOGETHER TO EXPLAIN PATTERNS OF GLOBAL CLIMATE? Oceans/Continents Surplus/Deficit Energy Global Pressure Belts Pressure Gradients Coriolis Effect Wind Direction • p. 46

  45. At the SURPLUS REGION: More insolation: “continents heat faster than oceans”. At Equator (LowPressure Belt): L intensifies over the continents  hot (warm) Ocean  cool L L L L = Low Pressure (warmer air, low density: air rises) • p. 46

  46. H H H At the SURPLUS REGION: More insolation: “continents heat faster than oceans”. • At Sub-Tropical H Belt (30° lat.): • High pressure is intensified over “cooler” oceans. • Oceans become cooler than continents. • Oceans  colder • Continent  warmer H = High Pressure (cooler air, high density: air sinks) • p. 46

  47. L L L At the DEFICIT REGION: Lack of insolation: “continents cool faster than oceans”. At Planetary Front 45-60 lat (Low Pressure): Low pressure is intensified over the oceans (warm/hot) Continent  cool Ocean  warm

  48. H H H At the DEFICIT REGION: Lack of insolation: “continents cool faster than oceans”. At the Poles 90 lat (High Pressure): High Pressure is intensified over continents. Ocean  Warm continent  cold

  49. 90°N • p. 46 OCEAN CONTINENT CONTINENT 90°S

  50. 90°N 45° - 60°N 30°N 0° 30°S 45° - 60°S 90°S