Lecture 8- Dynamic Theory of Ocean Tides Flashcards
1
Q
Why do we get ocean tides but no tides in lakes and ponds?
A
- ocean tides are pinched upward from the cumulative lateral pull by the moon
- lakes are not large enough to experience the broad lateral pinch
2
Q
wavelength of tide wave
A
- order of 1/2 the circumference of the earth
- 20,000 km
3
Q
tide wave depth
A
can be considered a shallow water wave for bottom depth < 1000 km
4
Q
dynamic theory of tides
A
- treated as forced shallow water wave
- not in equilibrium with lunar/solar forcing
- affected by Coriolis Force
- continents interfere with propagation of the tide wave
5
Q
forced shallow water waves
A
- shallow water causes the tide waves to move slower than the moon wants
- result is that the high tide occurs sometime AFTER the moon passes overhead
6
Q
Coriolis Force
A
- acts directly to the right in the northern hemisphere
- acts directly to the left in the southern hemisphere
7
Q
co-tidal lines
A
- line on a map connecting points at which a tidal level (especially high tide) occurs simultaneously
- diagonal lines
8
Q
co-range
A
blue concentric circles
9
Q
amphidromic point
A
- no tide point in the ocean or sea
- point around which the crest of the tide wave rotates during one tidal period
10
Q
as you move away from the amphidromic point
A
the difference between high and low tide become greater
11
Q
tidal ranges can be exaggerated by
A
- forcing ocean water into narrow embayment
- tidal forcing is in resonance with the tide wave
