Motion in the Ocean

Currents, Waves, Winds, and Tides

Answer the following questions at the top of your notes.

The following movements are caused by what?

1. Currents in the water2. Wind and Weather3. Waves4. Tides

Currents

Current Flow Activity

1. When warm water meets cold water what happens?Sketch and explain the results of the demonstration

2. When salt water meets fresh water what happens?Sketch and explain the results of the demonstration

Figure 3.16a

Figure 3.16b

Figure 3.16c

Figure 3.17

Figure 3.15b

Uneven heating of Earth’s surface causes atmospheric circulation

60% of heat transport is carried by atmosphere through storms thatMove along pressure gradients

40% is carried by ocean currents (conveyor belt) surface (warm) currents move poleward deep (cold) currents move equatorward

Ocean currents move 40% of “excess heat” from equator to poles

Driven by circulation of deep ocean waters Deepwater formation occurs near Greenland and in Antarctic

Movement of the ocean currents and winds are

also caused by the movement of the earth!

Earth is round and rotating east so water and wind are deflected to the right in N.

Hemisphere and left in S. Hemisphere

Figure 3.18c

Figure 3.23

The Pacific Ocean strongly influences the climate system because it is the largest ocean basin.

Figure 3.19

Figure 3.20

WINDS

vertical circulationAir rises at equator and subsides at poles

Circulation cells explain global distribution of rainfall

horizontal circulationEarth’s rotation determineswind direction (Coriolis force) tropical easterlies temperate westerlies

El Niño creates warmwinters in California

Seasonal variation in climate results from tilt in Earth’s axis Changes sun angle and day length

Figure 3.24

The wind not only drives currents but it

causes waves

Waves are caused by the strength of the wind and the fetch

Fetch= amount of distance the wind

blows across

Figure 3.27

Pg. 59

Tides

• Tides are huge shallow water waves.

• They are caused by:- Gravitational force of moon and sun- Motion of the earth

Tides

• Tides are periodic, short-term changes in the height of the ocean surface at a particular place, due to gravitational attraction of the moon and sun and the motion of the earth.

• Wavelength can be one half of the circumference of the earth.

Tides

• Moon has greatest effect on tides

• Sun has about one half the effect

Figure 3.29

1

2

3

4

5

67

8

Spring tides (springen - “to move quickly”)

During full and new moonsMost extreme tides

Neap tide (naepa - “hardly disturbed”)

During quarter moonsLeast extreme tides

Figure 3.31

Types of tides

Diurnal (one low, one high per day)

Semidiurnal (two lows, two highs per day)

Mixed (lows and highs are unequal)

Figure 3.32a

Figure 3.32b

Figure 3.32c

Figure 3.33