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) N 2, O 2, 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

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

Cells and surface winds Surface winds flow from high pressure to low pressure Fig. 7-10

Surface winds Tradewinds About 0 o to 30 o N and S Northeast (Northern hemisphere) Southeast (Southern hemisphere) Westerlies About 30 o to 60 o 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 H 2 O and CO 2

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

CO 2 in oceans CO 2 high solubility in seawater Excess CO 2 in atmosphere locked up in oceans CaCO 3 biogenic sediments Stimulate growth of phytoplankton to use up CO 2 in ocean

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

End of Chapter 7: Air-Sea Interaction