Factors Influencing Waves
1. Wind Speed
- Description: The speed at which the wind blows across the water surface.
- Influence: Higher wind speeds generate larger waves due to increased energy transfer.
- Example: During a storm, strong winds create large, powerful waves.
2. Wind Duration
- Description: The length of time the wind blows over the water.
- Influence: Longer wind durations allow for the build-up of larger waves.
- Example: Persistent winds blowing for several days across the ocean can generate large swell waves that travel long distances.
3. Fetch
- Description: The distance over which the wind blows across the water.
- Influence: A longer fetch allows for the accumulation of energy, creating larger waves.
- Example: In large oceanic expanses, such as the Pacific Ocean, the fetch can be vast, resulting in significant wave heights.
4. Water Depth
- Description: The depth of the water over which the wave is traveling.
- Influence: In shallow water, waves slow down, increase in height, and can break, while in deep water, waves maintain their speed and shape.
- Example: Waves approaching a coastline become steeper and break as the water shallows.
5. Ocean Currents
- Description: Large-scale water movements in the ocean.
- Influence: Currents can modify wave patterns by altering their direction and speed.
- Example: The Gulf Stream can affect wave patterns along the eastern coast of North America.
6. Geological Features
- Description: Physical features such as reefs, sandbars, and headlands.
- Influence: These features can influence wave height and direction through refraction, diffraction, and reflection.
- Example: Coral reefs can create large breaking waves ideal for surfing by refracting incoming wave energy.
Factors Influencing Tides
1. Gravitational Pull of the Moon
- Description: The Moon’s gravitational force on Earth’s oceans.
- Influence: The primary driver of tidal movements, causing high and low tides.
- Example: The highest high tides occur when the Moon is closest to Earth (perigee).
2. Gravitational Pull of the Sun
- Description: The Sun’s gravitational influence on Earth’s oceans.
- Influence: While less influential than the Moon, the Sun contributes to the overall tidal effect.
- Example: Spring tides, which have the greatest tidal range, occur when the Sun, Moon, and Earth are aligned during full and new moons.
3. Earth’s Rotation
- Description: The rotation of Earth on its axis.
- Influence: Causes the movement of tidal bulges around the planet, leading to regular high and low tides.
- Example: The diurnal and semidiurnal tidal patterns observed in different regions.
4. Earth-Moon-Sun Alignment
- Description: The relative positions of the Earth, Moon, and Sun.
- Influence: Creates varying tidal ranges depending on alignment.
- Example: Neap tides occur when the Moon and Sun are at right angles to Earth, resulting in lower high tides and higher low tides.
5. Coastal Topography
- Description: The shape and features of the coastline.
- Influence: Can amplify or diminish tidal ranges and patterns.
- Example: The funnel-shaped Bay of Fundy amplifies tidal ranges, resulting in some of the highest tides in the world.
6. Ocean Basin Shape and Size
- Description: The configuration of the ocean basins.
- Influence: Affects how tides propagate and interact with coastlines.
- Example: The Pacific Ocean’s large size and shape lead to complex tidal patterns compared to smaller basins like the Mediterranean Sea.
Example to Illustrate Factors Influencing Waves and Tides
Example: Coastal Town during a Storm
- Waves: In a coastal town, a storm is approaching. The wind speed picks up significantly (high wind speed), and it has been blowing steadily for several hours (long wind duration) across the open ocean (large fetch). As the storm moves towards the shore, the waves grow larger and more powerful due to the continuous energy transfer from the wind. As these waves move into shallower waters near the coast (water depth), they become steeper and eventually break, creating dangerous surf conditions. The presence of a nearby reef (geological feature) causes the waves to break further offshore, forming large breakers ideal for experienced surfers but hazardous for casual swimmers.
- Tides: The same coastal town experiences a full moon, meaning the gravitational pull of the Moon is at its peak. This alignment with the Sun (Earth-Moon-Sun alignment) causes spring tides, resulting in higher than usual high tides and lower than usual low tides. The town is located in an area with a pronounced coastal topography, where the shoreline forms a narrow bay that funnels the tidal waters, increasing the tidal range. As a result, during high tide, the water level rises significantly, flooding low-lying areas and affecting local infrastructure. Conversely, during low tide, vast stretches of the seabed are exposed, revealing tidal flats that are usually underwater.
