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Tides and Currents Waves

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All About Tides and Currents Waves

Seventy-one percent of Earth’s surface is covered by the ocean, a giant body of saltwater. Our planet Earth actually has one global ocean but the countries of the world and the oceanographers have divided this single ocean into four different regions namely; the Indian ocean, Arctic ocean, Antarctic ocean, and Pacific ocean.


Around ninety-seven percent of water in the world is found in the oceans, hence the ocean wave has a tremendous effect on the temperature, weather, and food supply of organisms on earth. From towering mountain ranges to deep canyons (called trenches), the ocean contains all of it (just like land).


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The ocean is never stationary. When we look out at the ocean, we can see an infinite series of waves moving water from one place to another. These tides and waves do result in the movement of surface water, but the notion of waves as traveling bodies of water is a bit misleading. Ocean wave are actually energy moving through water that causes it to move in a circular motion. Ocean tides and waves occur under the influence of various physical characteristics like wind, salinity, temperature, density, etc. Based on these factors, and a few other external factors like sun, moon, and wind, ocean movements are categorized into three different types ie., currents, waves and tides.


This article will look into all the three types, the difference between waves and currents, the difference between waves and tides, and also learn factors affecting the movement of ocean water.


Types of Waves Ocean

Governing principles of Chemistry and Physics are behind ocean movements where density, friction, and drag come into play and define the nature of tides and waves. Waves do not transmit water rather they transmit energy across the ocean. If this energy is not obstructed, they have the capacity to travel across a whole ocean basin.


Waves, tides and currents are the three kinds of natural phenomena occurring in water. All the three are similar in nature but not the same. The difference in them is due to the intensity, what causes them, and frequency (among few other other factors). 


These natural phenomena drive the sea but the ocean by itself does not generate any of these three motions. For example, waves are influenced by wind’s actions on the ocean's surface whereas currents are impacted by the Sun's heat coming from the equator and cooler poles. Tides occur due to the gravitational forces of the moon and sun.

  • Waves - When the wind blows over any area of the ocean, it causes perturbations which results in waves. The friction between surface water and wind creates an oscillatory movement, resulting in the rise and fall of water.

    • Waves are the oscillatory motion of water.

    • A wave consists of crests (the raised part) and troughs (the lowest point).

    • Despite a large amount of momentum and energy in waves, the individual water particles in the wave have very little forward motion.

    • Each water particle in a wave moves in a circular motion.

    • Waves have a measurable height which is the distance from their crest to trough.

    • There are three major factors that affect waves in the ocean, they are:

      • Velocity or speed of the wind.

      • The distance that the wind covers over the ocean.

      • The duration of wind blowing over the ocean.

  • Tides - Tides are waves with very long periods and occur once or twice a day. Tides are a response to the gravitational forces exerted by the sun and moon. Moon’s gravitational pull has more impact on tides as it is closer to earth.

  • Tides are vertical movements of water.

  • Originating in the ocean, tides move to coastlines where they look like the regular rise and fall of seas.

  • A high tide corresponds to the crest of a wave reaching a specific location, and a low tide corresponds to a tidal wave’s trough.

  • The tidal range is the difference in height between a high and low tide.

  • Tidal currents are tides channeled into estuaries, between islands, or bays.

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  • Currents - Currents are formed when large masses of ocean water move horizontally in one specific direction over long distances. The rotation of the earth largely determines the motion and direction of ocean currents.

    • Three factors cause ocean currents:

      • Prevailing winds

      • Rise and fall of tides

      • The difference in salinity and temperature of ocean water causes density differences.

    • In the northern hemisphere, most currents move in a clockwise fashion due to Coriolis force, while those in the southern hemisphere move in an anti-clockwise direction.

    • Ocean currents can flow a very large distance and together they create the global conveyor belt. The global conveyor belt has a major role in determining the climate of many regions on the earth.


Conclusion:

The ocean is affected by three types of natural phenomena which are waves, tides, and currents. All these three oceanic motions are caused by different things like the wind (waves), the gravitational pull of the moon and sun (tides), and temperature, salinity, or density differences on the surface of an ocean (current). Hopefully, the article covered all about the currents waves and tides in detail. 

FAQs on Tides and Currents Waves

1. What is the main difference between ocean waves and tides?

The main difference lies in their cause and scale. Ocean waves are surface movements, usually caused by wind pushing on the water. They are about energy moving through water. Tides, however, are the large-scale rise and fall of the entire sea level, caused by the gravitational pull of the Moon and the Sun.

2. What are ocean currents and what makes them move?

Ocean currents are like massive rivers flowing within the ocean. They are continuous, directed movements of seawater. Their movement is primarily driven by a combination of factors, including wind, water temperature differences, and variations in water salinity (saltiness). These currents play a crucial role in distributing heat around the planet.

3. What are the main types of tides based on their frequency?

Tides are classified into three main types based on how often they occur each day:

  • Semi-diurnal tide: Features two high tides and two low tides each day, with both high tides being of similar height.
  • Diurnal tide: Has only one high tide and one low tide each day.
  • Mixed tide: A tide with two high and two low tides of different heights in a day.

4. How do the Sun and Moon create spring and neap tides?

The positions of the Sun and Moon relative to Earth determine the strength of tides. When the Earth, Moon, and Sun are aligned (during a full moon or new moon), their combined gravitational pull creates extra-high high tides and extra-low low tides, known as spring tides. When the Moon and Sun are at a right angle to the Earth, their gravitational forces partially cancel each other out, leading to weaker tides with a smaller range, known as neap tides.

5. Why are ocean currents so important for Earth's climate?

Ocean currents act like a global heating and cooling system. They transport huge amounts of warm water from the equator towards the poles and cold water from the poles back towards the equator. This constant circulation of heat helps to regulate global weather patterns and temperatures, making different regions of the world more habitable than they would be otherwise.

6. If a strong wind can create big waves, can it also create a tide?

No, even the strongest wind cannot create a tide. Wind has enough energy to move the surface of the water and create waves, some of which can be very large during a storm. However, tides are caused by the immense gravitational force of the Moon and Sun, which is powerful enough to move the entire volume of the ocean, not just its surface.

7. What is the difference between an ocean current and a tidal current?

An ocean current is a continuous, large-scale flow of water that circulates across entire oceans, driven by factors like wind and water density. A tidal current is the localised, temporary, and back-and-forth movement of water caused by the rising and falling of tides. Tidal currents are most noticeable near the coast, in bays, and in estuaries.