Coastal Geography, Tides

Question 1

Tide

Answer 1

Rise and fall of sea surface

Question 2

What three forces control the Earth’s tides?

Answer 2

The gravitational pull of the Sun and Moon, and the rotation of Earth

Question 3

Primary bulge

Answer 3

Occurs on the near side facing the moon due to gravity

Question 4

Secondary bulge

Answer 4

Occurs on the far side not facing the moon due to inertia

Question 5

Diurnal inequality

Answer 5

Two high or low tides in the same day of unequal size

Question 6

What causes diurnal inequality?

Answer 6

Priamry bulge is larger than the secondary bulge

Question 7

Why does high tide occur every 12 hours and 25 minutes?

Answer 7

Not only is the moon rotating, but the moon is also orbiting arund the Earth. The Earth has to ‘catch up’ with the Moon to return to high tide

Question 8

Spring tide

Answer 8

Occurs when both the Sun and Moon are alligned either during new or full Moon

High tides ↑
Low tides ↓

Question 9

Neap tide

Answer 9

Occurs when the Sun and Moon are at right angles to each other when the Moon is in its first or third quarter

High tides ↓
Low tides ↑

Question 10

Perihelion

Answer 10

Earth nearest to Sun

Question 11

Aphelion

Answer 11

Earth furthest from Sun

Question 12

Perigee

Answer 12

Moon nearest to Earth

Question 13

Apogee

Answer 13

Moon furthest from Earth

Question 14

Tidal range

Answer 14

Difference in height between high and low tide

Question 15

What classifies a micro, meso, and macrotidal range?

Answer 15

Micro: 0 - 2m
Meso: 2 - 4m
Macro: >4m

Question 16

What is the general relationship between the lunar and solar tide?

Answer 16

The lunar tide is the ‘actual tide’ which is modified by the solar tide

Question 17

Conjunction tide

Answer 17

Type of spring tide when the Sun and Moon are on the same side of the Earth

Question 18

Opposition tide

Answer 18

Type of Spring tide when the Sun and Moon are on opposite sides of the Earth

Question 19

Quadrature tide

Answer 19

A type of neap tide when the lunar and solar tide counteract each other

Question 20

Coriolis force

Answer 20

Because of the Earth’s rotation, wind (and therefore currents) are deflected from a straight path.

Northern hemisphere: Deflect to the right

Southern hemisphere: Deflect to the left

Question 21

How does continetial shelf affect tides?

Answer 21

Wide continential shelves have larger tidal ranges as wave shaoling causes crests to become amplified.

Contrarily, narrow continential shelves have smaller tidal ranges as the continential slope is far steeper, decreasing the period of amplification potential.