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Air & Sea Interactions

Air & Sea Interactions. Points to Remember. Water takes longer to heat up and cool down due to hydrogen bonds. Points to Remember. Warm air can hold more water vapor than cold air. Points to Remember. Uneven heating of the Earth’s surface leads to wind/convection. Points to Remember.

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Air & Sea Interactions

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  1. Air & Sea Interactions

  2. Points to Remember • Water takes longer to heat up and cool down due to hydrogen bonds

  3. Points to Remember • Warm air can hold more water vapor than cold air

  4. Points to Remember • Uneven heating of the Earth’s surface leads to wind/convection

  5. Points to Remember • Global Wind Patterns: • Doldrums • Trade Winds • Westerlies • Easterlies

  6. Points to Remember • The Coriolis Effect will cause northward and southward traveling objects/wind to have a perceived curved trajectory

  7. Points to Remember • Global Conveyor Belt’s movement is based on salinity and temperature differences.

  8. Atmospheric Circulation Cells • Six distinct air masses (three in each hemisphere) with individual airflow patterns

  9. Hadley Cells • Air rises from equator (doldrums) • Moves towards the poles due to convection • Sinks at 30 degrees latitude due to cooling and moisture loss (creates deserts) • Moves back towards the equator • Bends right as it heads towards the equator creating Trade winds

  10. Ferrel Cells • Some air that rose at the equator continues towards the poles • Bends to the right creating the Westerlies

  11. Polar Cells • Warm air rises at 60 degrees latitude and flows towards to the poles • It cools and descends at the poles and heads back towards the equator, deflected right to form the polar easterlies

  12. Intertropical Convergence Zone • Vertical motion of the air near the equator that releases large amounts of heat and moisture into the atmosphere • Strongly influences climate, weather, and the seasons • Constantly shifting above and below the equator due to land masses • Atmosphere circulation symmetrical above and below the ITCZ not the equator

  13. Intertropical Convergence Zone

  14. El Nino Southern Oscillation • El Nino - A build up of warm water in the oceans near the equator just east of Asia which leads to global weather and climate changes • Occurs every three to eight years

  15. Normal Conditions: • Trade winds blow strongly along the equator, winds blowing parallel to South American coast creates a rising thermocline called an upwelling (rising of nutrient rich/cold seawater)

  16. Normal Conditions: • Upwelling makes the temperature of surface water cooler • Warm water builds up in Western Pacific • Results in low pressure and high rainfall in Western Pacific (Southeast Asia) and high pressure and low rainfall in Eastern Pacific (Americas)

  17. El Nino Conditions • Trade winds weaken, stop or reverse course (blow East) • Warm water that is normally pushed west now spreads out into the ocean and towards the East • Thermocline deepens as a result and upwelling does not reach surface with cold water, causing Eastern Pacific to be warmer

  18. El Nino Conditions • Since there is less of a temperature difference between the Western and East Pacific, trade winds become even more weak • Results in more rain and warmer temperatures in the Americas • Arrives around Christmas time (called the current of the little boy/Christ child, hence the name El Nino) • Loss of nutrients from the loss of upwelling collapses the fishing industry and marine ecosystems

  19. Global Effects of El Nino • Causes the hottest part of the troposphere to move 1/3 around the world • Leads to extensive extreme weather conditions, flooding, tornados, and drought • Destroys ecosystems

  20. La Nina • After an El Nino, the normal conditions return in extreme forms leading to colder than normal ocean conditions in the Eastern Pacific

  21. Monsoons • Seasonal wind pattern changes caused by heating or cooling on the continents that lead to predictable times of massive rainfall or dry conditions • Results in summers with significant rainfall and winters with very little • Caused by air heated by landmass rises and is replaced by warm, moist air from the ocean, which in turn rises and causes rainfall, Cycle reverses in winter

  22. Cyclones • Large rotating storm centers of low pressure air, with converging winds at the center, known as hurricanes (Asia – Typhoons) • Two Types: • Tropical –cyclones that form within a single atmospheric cell • Extratropical – cycles that form in high latitudes, not as severe, lead to “nor’easters”

  23. Tropical Cyclones • Moist winds get drawn into a low pressure area (air moves from high to low pressure) • The Coriolis Effect causes the winds to spiral inward and counter clockwise in the Northern Hemisphere • Warm air rises in the center via convection causing rain

  24. Tropical Cyclones • The formation of rain heats the atmosphere which causes air pressure to continue to decrease and pull more air into the system • So long as there is moisture and heat, the process continues to intensify, possibly into a hurricane

  25. Simple Explanation • The sun heats the ocean, the ocean heats the air, the air rises • Warm air is less dense and therefore it rises and thus it has a low pressure • As the moist air rises, it condense and forms clouds and precipitation • Air rushes in to replace the air that rose, and brings with it more heat and moisture • The air rushing in deflects to the right due to the Coriolis Effect causing a counter-clockwise rotation • This leads to a tropical cyclone

  26. Hurricane Recipe: • Area of warm water • Winds affected by the Coriolis Effect (no hurricanes at the equator nor can they cross the equator) • A collection of storms

  27. Tropical Cyclone Designations • Tropical Disturbance – a low pressure system with a group of storms, little to no rotation • Tropical Depression – A tropical cyclone with max sustained winds up to 38 mph • Tropical Storm – A tropical cyclone with max sustained winds of 39-73 mph (naming stage) • Hurricane – A tropical cyclone with max sustained winds of 74-110 mph • Major Hurricane – A tropical cyclone with max sustained winds of 111+ mph, Category 3 or above

  28. Path of a Hurricane • Trade winds direct it initially to the west, then as it increases in latitude, Westerlies will push it East

  29. Saffir-Simpson Scale • Categories of hurricanes are determined by wind speed and air pressure. The resultant of which determine storm surge and potential damage

  30. Naming System • Named alphabetically • Alternate boy/girl • Retire names of the worst storms

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