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