Movements of Ocean Water

Ocean water exhibits a dynamic nature. It is because its physical properties are influenced by temperature, density, salinity, and gravitational pull of the moon and sun. Even winds influence its movement. 

Common Horizontal and Vertical Motions in Ocean Water Bodies

• The Horizontal Motion:

The Horizontal Motion is determined by the ocean waves and currents. 

• Ocean Waves:

Wave is the movement of the ocean water in horizontal direction. The water itself does not move but in fact, the wave trains travel ahead. 

• Ocean Currents:

When a huge quantity of water moves in a single direction, ocean currents are formed. Ocean currents help water to move from one point to another. 

• The Vertical Motion:

  • When the water rises or falls in the seas or oceans, tides are formed. Therefore, when we speak of tides, we are referring to the vertical motion of ocean water
  • The gravitational pull of the moon and the sun makes the ocean water rise up and down forming a high tide and a low tide. This phenomenon happens twice every day
  • Vertical motion is also formed due to a process known as cold water’s upwelling from the subsurface. Similarly, when surface water sinks down, it also gives rise to vertical motion

Waves 

• When we speak of waves, we speak of energy that moves from one point of the ocean to another. It does not concern the ocean water directly 
• When a wave moves, the particles move only in a small circle
• Waves get energy from the wind which causes it to move in the ocean. This energy is finally released as the waves hit the shore 
• The movement of the surface water does not influence the deep water at the bottom that remains stagnant
• The speed of the waves gets reduced as the wave moves towards the beach. It happens due to the friction created between moving water and the sea floor
• When the water’s depth is less than 50% of the wave’s length, it breaks
• The waves mostly form as the winds blow against the water
• Open oceans have the biggest waves
• The ripples continue to grow while travelling and get energy from the wind to move forward
• Small ripples are created when a breeze of 2 knots drives against a calm water. These ripples grow as the speed enhances. The waves break, white caps are created that finally stops the waves from growing
• The waves have the capacity to move thousands of kilometres before breaking, dissolving in the form of surf, or reaching the shore
• The shape and size of a wave exposes its origin
• Steep Waves: The waves that are relatively young and created by local wind are called steep waves 
• Slow & Steady Waves: The slow and steady waves usually come from distant places (sometimes from the other hemisphere)
• The height of a wave is maximum when the wind blows strong and for a long time. Also, the direction of the wind and the region over which it blows also play a pivotal role in wave height
• As the wind pushes the water body in its course, waves move forward while gravity pulls them back from the crest to the trough. It is actually the troughs that fall down and rise up causing the wave to move from one position to another
• Below the waves, water moves in a circular motion. It reveals that things will rise and move forward as the wave approaches. These things move in the downward and backward direction as the wave passes 

Characteristics of Waves 

• Trough & Wave Crest – Crest is the highest point of a wave whereas trough is the lowest point
• Wave Height – The vertical distance measured from a wave’s trough to its crest is called the wave height
• Amplitude of Wave: When a wave is divided by two, it becomes its amplitude
• Wave Period – The period between 2 successive troughs and crests as they move a fixed point is called a wave period
• Wave Length – The horizontal distance between 2 successive crests is called the length of the wave
• Wave Speed – The rate at which the wave travels through the water is called wave speed. ‘Knots’ is the unit of wave speed
• Wave Frequency – The number of waves travelling through a given point in 1 one second is the wave frequency

Conclusion

The ocean water is never still. There are different types of movements of ocean water under the influence of different physical characteristics like temperature, salinity, density, etc. Movements of ocean water are also affected by external forces like the sun, moon and the winds.