Chapter 7: Air-Sea Interaction
Fig. 7-20
Atmosphere and ocean one interconnected system
Change in atmosphere affects ocean
Change in ocean affects atmosphere
Unequal solar heating
Low latitudes receive more solar radiation
High latitudes receive less solar radiation
Equatorial areas excess heat Polar regions heat deficient
Fig. 7-3
Insolation factors
Latitude Thickness of atmosphere Albedo Seasons Time of day Vegetation, bare rock, etc.
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
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
Coriolis Effect Videos Click on Picture to See
How It Works Click on Picture to at Equator
vs. N. Hemisphere vs. S. Hemisphere
Atmospheric circulation
Hadley, Ferrell and polar cells Warm, moist air rises
Equator Sub-polar lows (60o N and S)
Cool, dry air sinks Sub-tropical highs (30o N and S) Polar regions
Windbelts
Cells and surface winds Surface winds flow from high pressure to
low pressure
Fig. 7-10
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
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
Local winds and their effects
Sea breeze Land breeze Sea fog Radiation fog
Air masses meet at low pressure
Fig. 7-14
Regional winds and storms
Mid-latitude storm systems Low
pressure Warm front Cold front
Fig. 7-15
Hurricane (tropical cyclone)
Develop over tropical ocean
Warm ocean Warm, moist air
rising Sufficient
Coriolis Effect to cause rotation
Fig. 7-17
Tropical cyclones
Destructive high winds, storm surge
Classified by damage done/wind speed
Moved westward by trade winds
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)
Greenhouse effect
Energy from Sun shorter wavelengths
Energy reradiated from Earth longer wavelengths
Fig. 7-24
Greenhouse gases Absorb infrared radiation from Earth Mainly H2O and CO2
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
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
SOFAR Channel
Sound travels far Velocity of sound is temperature-dependent
Use sound to measure temperature in much of ocean
ATOC (Acoustic Thermometry of Ocean Climate)
End of Chapter 7: Air-Sea Interaction