Chapter 7: AirSea Interaction

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Chapter 7 Air-Sea Interaction
Fig. 7-20
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• Atmosphere and ocean one interconnected system
• Change in atmosphere affects ocean
• Change in ocean affects atmosphere

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Unequal solar heating

• Low latitudes receive more solar radiation
• High latitudes receive less solar radiation

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• Equatorial areas excess heat
• Polar regions heat deficient

Fig. 7-3
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Insolation factors

• Latitude
• Thickness of atmosphere
• Albedo
• Seasons
• Time of day
• Vegetation, bare rock, etc.

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Atmosphere (troposphere)

• N2, O2, Ar
• Temperature decreases with increasing altitude
• Warm air is less dense than cool air
• Moist air is less dense than dry air
• Wind flows from high pressure to low pressure

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Coriolis Effect

• Deflection in motion of moving objects
• Rotation of Earth
• Important for objects that move long
  distances/long times
• Maximum deflection at poles
• Negligible deflection at equator

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Atmospheric circulation

• Hadley, Ferrel and polar cells
• Warm, moist air rises
• Equator
• Subpolar lows (60o N and S)
• Cool, dry air sinks
• Subtropical highs (30o N and S)
• Polar regions

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Cells and surface winds

• Surface winds flow from high pressure to low
  pressure

Fig. 7-10
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Surface winds

• Tradewinds
• About 0o to 30o N and S
• Northeast (Northern hemisphere)
• Southeast (Southern hemisphere)
• Westerlies
• About 30o to 60o N and S
• Polar Easterlies

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Idealized 3-cell model

• Complicated by
• Seasons, tilt
• Differences in heat capacities of land and ocean
• Uneven distribution of land and ocean
• Example monsoon winds in Asia and Indian Ocean

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Local winds and their effects

• Sea breeze
• Land breeze
• Sea fog
• Radiation fog

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Air masses meet at low pressure
Fig. 7-14
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Regional winds and storms

• Mid-latitude storm systems
• Low pressure
• Warm front
• Cold front

Fig. 7-15
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Hurricane (tropical cyclone)

• Develop over tropical ocean
• Warm ocean
• Warm, moist air rising
• Sufficient Coriolis Effect to cause rotation

Fig. 7-17
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Tropical cyclones

• Destructive high winds, storm surge
• Classified by damage done/wind speed
• Moved westward by trade winds

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Sea ice vs. icebergs

• Sea ice frozen seawater
• Especially important in Arctic
• Pack ice, polar ice, fast ice
• Icebergs broken pieces of glacier
• Float in ocean
• Shelf ice (extremely large plate-like icebergs)

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Greenhouse effect

• Energy from Sun shorter wavelengths
• Energy reradiated from Earth longer wavelengths

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Fig. 7-24
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Greenhouse gases

• Absorb infrared radiation from Earth
• Mainly H2O and CO2

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Other greenhouse gases

• Minor gases methane, nitrous oxides, ozone,
  chlorofluorocarbons
• Anthropogenic sources of greenhouse gases
  contribute to global warming
• Increase in global temperature
• Some natural
• Most artificial

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CO2 in oceans

• CO2 high solubility in seawater
• Excess CO2 in atmosphere locked up in oceans
• CaCO3 biogenic sediments
• Stimulate growth of phytoplankton to use up CO2
  in ocean

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SOFAR Channel

• Sound travels far
• Velocity of sound is temperature-dependent
• Use sound to measure temperature in much of ocean
• ATOC

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End of Chapter 7 Air-Sea Interaction