Tides Flashcards
Which type of wave have he longest wavelength?
Tides
What are tides?
Periodic short term changed in the height of the ocean surface due to gravitational interactions between the earth moon and sun
What is the equilibrium theory?
Simplified model. Moon has twice the influence because it’s closer to earth. Lunar tides dominate while solar tides only become significant twice a month.
What are lunar bulges? Equilibrium theory
Ocean bulges caused by moon. Occur twice. One is gravitational one is inertia directly across from each other. Cause two high tides and two low tides per day.
How long is a tidal day? Equilibrium theory
24 hours 50 minutes
What are spring tides? Equilibrium theory
When moon and sun are in alignment tides have Larger than normal tidal range. Higher high tides and lower low tides. Occur twice a month during new and full moon
What are neap tides? Equilibrium theory
Moon & sun @ 90 degrees smaller than normal tidal range. Lower high tides and higher low tides. Occur 2x a month
What are some problems with equilibrium theory?
Real tides are larger than theory suggests.
Continents interfere with tides.
Some places don’t have two full tidal ranges
What is the dynamic theory?
Mix of diurnal and semi diurnal tide cycles.
Dynamic- what are semidiurnal tides and where are they common?
Common along Atlantic and Arctic coasts. Two relatively equal high and low tides (2 of each)
What are diurnal tides? Dynamic
One high and one low tide separated by 12 hours. Common in Gulf of Mexico and NW Pacific
What regions have both types of tides in dynamic theory?
Much of pacific and parts of Mediterranean Sea
What type is places experience tidal currents?
Areas with large ranges in tidal height
What are flood tides?
Rapid sea level increase due to large incoming high tides
Why are ebb tides?
Rapid fall of sea level due to outgoing low tides
