Circulation of the Air and Circulation of the Air and OceansOceans

I. Air CirculationI. Air Circulation

A.A. Uneven heating of earth’s Uneven heating of earth’s surfacesurface

B.B. Seasonal changes in Seasonal changes in temperature & precipitationtemperature & precipitation

C. Rotation of the earth on its C. Rotation of the earth on its axisaxis

Coriolis Effect—because the Coriolis Effect—because the earth is rotating anything that earth is rotating anything that moves over its surface tends moves over its surface tends to turn to one side rather than to turn to one side rather than moving in a straight line. moving in a straight line.

• deflection of winds to right in deflection of winds to right in N and left in SN and left in S

II. Chemical Make-up of II. Chemical Make-up of AtmosphereAtmosphere

A. Greenhouse GasesA. Greenhouse Gases Traps energy from Traps energy from

escaping atmosphere escaping atmosphere warming airwarming air

B. Greenhouse EffectB. Greenhouse Effect Natural warming of Natural warming of

atmosphereatmosphere Necessary for EarthNecessary for Earth

C. Global WarmingC. Global Warming

Unnatural warming of the EarthUnnatural warming of the Earth Caused by human activity; ie burning of Caused by human activity; ie burning of

fossil fuelsfossil fuels Increase greenhouse gases in atmosphere Increase greenhouse gases in atmosphere

to unnatural levelsto unnatural levels Heavily debated as to rate of occurenceHeavily debated as to rate of occurence

D. Ozone LayerD. Ozone Layer

Oxygen(OOxygen(O22) )

conversion to Ozone conversion to Ozone (O(O33))

Prevents 95% of UV Prevents 95% of UV radiation from radiation from reaching earth’s reaching earth’s surfacesurface

E. Depletion of Ozone LayerE. Depletion of Ozone Layer

CFCs in atmosphere due to human activityCFCs in atmosphere due to human activity C,F, Cl break apart bonds between C,F, Cl break apart bonds between

oxygen moleculesoxygen molecules Result in new compounds; less ozoneResult in new compounds; less ozone UV radiation allowed to reach earth’s UV radiation allowed to reach earth’s

surfacesurface DNA mutationsDNA mutations

III. Ocean CurrentsIII. Ocean Currents

A. Large scale currentsA. Large scale currents

1. Gyre1. Gyre – large circular – large circular systems of surface currents; systems of surface currents; redistribution of heat & redistribution of heat & moisture; warm the western moisture; warm the western sides of oceans; ex. Gulf sides of oceans; ex. Gulf Stream along eastern US coastStream along eastern US coast

2. Upwelling2. Upwelling —cold, nutrient —cold, nutrient rich bottom water move to the rich bottom water move to the surface along steep coastlinessurface along steep coastlines

Ocean Currents, cont.Ocean Currents, cont.

3. Thermohaline – 3. Thermohaline – changes in density from changes in density from temperature & salinity changes; vertical movement; temperature & salinity changes; vertical movement; downwelling = sinking of more dense water; upwelling = downwelling = sinking of more dense water; upwelling = rising of less dense waterrising of less dense water

a. a. North Atlantic Deep WaterNorth Atlantic Deep Water

b. b. Antarctic Bottom WaterAntarctic Bottom Water – denser, moves under – denser, moves under NADW, causes upwellingsNADW, causes upwellings

4. Thermocline – 4. Thermocline – changes in temperature cause changes in temperature cause circular currents in the water columncircular currents in the water column

Ocean Currents, cont.Ocean Currents, cont.

B. Smaller scale currentsB. Smaller scale currents

1. Longshore current – 1. Longshore current – travels north to south, travels north to south, causes sand to move from north end of islands to south causes sand to move from north end of islands to south end - “River of Sand” (barrier islands erode on N and end - “River of Sand” (barrier islands erode on N and grow on S), caused by swash and backwash, creates a grow on S), caused by swash and backwash, creates a spit on the island (hook shape on S end); people attempt spit on the island (hook shape on S end); people attempt to stop the erosion by building jetties/seawalls, moving to stop the erosion by building jetties/seawalls, moving the sand, etcthe sand, etc

Ocean currents, cont.Ocean currents, cont.

2.2. Waves Waves caused by wind energycaused by wind energy wind transfers some of its energy to the water through friction wind transfers some of its energy to the water through friction

between the air molecules and the water molecules between the air molecules and the water molecules size depends on velocity of wind, length of time wind blows, size depends on velocity of wind, length of time wind blows,

fetch (distance the wind blows) fetch (distance the wind blows) water molecules move in circular patternwater molecules move in circular pattern energy transferred from molecule to molecule as wave moves; energy transferred from molecule to molecule as wave moves;

upon breaking, energy is transferred to the beach (erosion and upon breaking, energy is transferred to the beach (erosion and sediment deposition)sediment deposition)

TidesTides

Tides are periodic rises and falls of large Tides are periodic rises and falls of large bodies of waterbodies of water

Causes for TidesCauses for Tides Tides are caused by the gravitational Tides are caused by the gravitational

interaction between the Earth, the Moon, interaction between the Earth, the Moon, and the sun.and the sun. The gravitational attraction of the moon The gravitational attraction of the moon

causes the oceans to move out in the causes the oceans to move out in the direction of the moondirection of the moon

On the opposite side of the earth the ocean On the opposite side of the earth the ocean moves out as well due to the fact that the moves out as well due to the fact that the moon’s gravitational pull is at its weakest and moon’s gravitational pull is at its weakest and the earth itself is also being pulled in the the earth itself is also being pulled in the direction of the moondirection of the moon

Sun’s Interaction with TidesSun’s Interaction with Tides1.1. Spring TidesSpring Tides (they do not have anything to do with the season Spring)(they do not have anything to do with the season Spring)

are especially strong tidesare especially strong tides Occur when the Earth, Sun, and the Moon are in Occur when the Earth, Sun, and the Moon are in

a line.a line. The gravitational forces of the Moon and the Sun The gravitational forces of the Moon and the Sun

both contribute to the tides.both contribute to the tides. Spring Tides occur during the full and new moonSpring Tides occur during the full and new moon

2.2. Proxigean Spring TidesProxigean Spring Tides Rare and unusually high tideRare and unusually high tide Occurs when the moon is both unusually Occurs when the moon is both unusually

close (proxigee) to the Earth and in the new close (proxigee) to the Earth and in the new moon phase (when moon is between the moon phase (when moon is between the sun and the earth)sun and the earth)

Occurs at most once every 1.5 yearsOccurs at most once every 1.5 years

3.3. Neap TidesNeap Tides Very weak tidesVery weak tides Occur when the gravitational forces of the Occur when the gravitational forces of the

moon and the sun are perpendicular to one moon and the sun are perpendicular to one another (with respect to the Earth)another (with respect to the Earth)

Neap Tides occur during quarter moonsNeap Tides occur during quarter moons

Types of TidesTypes of Tides

Diurnal TidesDiurnal Tides

These tides have 1 high and 1 low tide per These tides have 1 high and 1 low tide per tidal daytidal day

Found in parts of the northern Gulf of Found in parts of the northern Gulf of Mexico and Southeast AsiaMexico and Southeast Asia

Semi-diurnal TidesSemi-diurnal Tides

These tides have 2 high and 2 low tides These tides have 2 high and 2 low tides per tidal dayper tidal day

Found on the Atlantic coasts of the United Found on the Atlantic coasts of the United States and EuropeStates and Europe

Mixed TidesMixed Tides

These tides have a high high tide, a low These tides have a high high tide, a low high tide, a high low tide, and a low low high tide, a high low tide, and a low low tidetide

Found around the west coast of Canada Found around the west coast of Canada and the United Statesand the United States