13 - Tides and Current Concepts Flashcards
Tides
Vertical rise and fall of the ocean due to the gravitational and centrifugal forces between the earth and the moon
Flood Tide
When the tide is rising
Ebb Tide
When the tide is falling
Stand
The period when no change in water level is detected
Range of Tide
Total rise or fall from consecutive low to high water
Semidiurnal Tide System
Primary type of tide
- 2 High tides
- 2 low tides
Diurnal Tide System
- 1 High tide
- 1 Low tide
Mixed semidiurnal Tide System
Varying points of high and low tides
- 2 High tides
- 2 Low tides
Duration of a Solar Day
24 Hours
Duration of a Tidal Day
24 Hours and 50 Minutes
What are the different types of phenomena?
- Spring Tide
- Neap Tide
Spring Tide
When the Sun and the Moon are in line with the Earth.
- Higher than average High Tides
- Lower than average Low Tides
Neap Tides
When the Sun and Moon are perpendicular to each other.
- Lower than average high tides
- Higer than average low tides
Tides
What do Currents result from?
- Daily changes in tidal levels
- Steady blowing of wind
- Normal flow of rivers from higher elevations at sea
- Waterfalls
- Long term climate or weather conditions
- Direction of current - Set
- Speed of current - Drift
Types of Currents
- Ocean
- Tidal
What is an Ocean current?
Well-defined permanent current systems in open ocean.
What is a Tidal current?
Most commonly dealt with current
Produced by rise and fall of water (tides)
What are the types of Tidal Currents?
- Reversing
- Rotary
What is a Reversing Current?
When the current moves toward and away from the shore.
What is a Rotary Current?
- Type of tidal current
- Geographic dependent
- Rotates 360º in a Tidal Day
