Transcript Chapter 7: Air-Sea Interaction

Chapter 7: Air-Sea Interaction
Fig. 7-20
Atmosphere and ocean one
interconnected system
 Change in atmosphere affects
ocean
 Change in ocean affects
atmosphere
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Unequal solar heating
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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
Insolation factors
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Latitude
Thickness of atmosphere
Albedo
Seasons
Time of day
Vegetation, bare rock, etc.
Atmosphere (troposphere)
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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
Coriolis Effect
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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
Atmospheric circulation
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Hadley, Ferrel and polar cells
Warm, moist air rises
Equator
o
 Subpolar lows (60 N and S)
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Cool, dry air sinks
Subtropical highs (30o N and S)
 Polar regions
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Cells and surface winds
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Surface winds flow from high pressure to low
pressure
Fig. 7-10
Surface winds
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Tradewinds
About 0o to 30o N and S
 Northeast (Northern hemisphere)
 Southeast (Southern hemisphere)
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Westerlies
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About 30o to 60o N and S
Polar Easterlies
Idealized 3-cell model
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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
Regional winds and storms
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Mid-latitude
storm systems
 Low
pressure
 Warm front
 Cold front
Fig. 7-15
Hurricane (tropical cyclone)
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Develop over
tropical ocean
Warm ocean
Warm, moist air
rising
Sufficient Coriolis
Effect to cause
rotation
Fig. 7-17
Tropical cyclones
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Destructive high
winds, storm
surge
Classified by
damage
done/wind speed
Moved westward
by trade winds
Sea ice vs. icebergs
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Sea ice frozen seawater
Especially important in Arctic
 Pack ice, polar ice, fast ice
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Icebergs broken pieces of glacier
Float in ocean
 Shelf ice (extremely large plate-like
icebergs)
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Greenhouse effect
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Energy from Sun shorter wavelengths
Energy reradiated from Earth longer
wavelengths
Fig. 7-24
Greenhouse gases
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Absorb infrared radiation from Earth
Mainly H2O and CO2
Other greenhouse gases
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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
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CO2 high solubility in seawater
Excess CO2 in atmosphere locked
up in oceans
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CaCO3 biogenic sediments
Stimulate growth of phytoplankton
to use up CO2 in ocean
SOFAR Channel
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Sound travels far
Velocity of sound is temperaturedependent
 Use sound to measure
temperature in much of ocean
 ATOC
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End of Chapter 7: Air-Sea
Interaction