Can you imagine some gravitational pull of the Sun and the Moon can affect the natural world here on Earth? This phenomenon is known as a tide that occurs in the ocean. In oceans, the rise and fall of the water is a regular and common phenomenon when these tides occur the waves move towards the shores and affect the coastlines as well as the maritime activities of the nations. These tides are of various types. In this article, we will be talking about some of its types such as spring and neap tides, the definition of spring tide or neap tide definition, perigean tide and all the related concepts. This topic will help you in Geography and Geology or Earth Sciences whenever you read about Oceanography.
Tides are the waves that occur through the regular change in the sea level caused by the moon and the sun. Tides emerge in the sea and go towards the coastlines. At the time of high tide, the sea is closer to the land and at the low tide it is farther away from and more of the beach can be seen. It is caused by the gravitational pull of the moon and the sun. It happens twice every day. Due to the change of the tides, the large quantities of water move towards or away from shore causing tidal currents.
Spring tide is one of the types of it. A tide that comes just after a new or full moon when there is a huge difference between high and low water. This is popularly known as a "King Tide" which refers to the "springing forth" of the tide during a new and full moon. It usually occurs three and four times in the year. This tide occurs at a couple of inches to normal spring tides. The term spring is derived from the concept of the tide "Springing forth". It occurs in the lunar month.
Spring Tide Definition
Some of the standard and recognised definitions are mentioned below:
"Either of the two tides that occur at or just after the new moon and full moon when the tide-generating force of the sun acts in the same direction as that of the moon, reinforcing it and causing the greatest rise and fall in tidal level. The highest spring tides (equinoctial springs) occur at the equinoxes." Or "A spring tide is an unusually high tide that happens at the time of a new moon or a full moon." - Collins dictionary.
"It is a tide of the greater-than-average range around the times of new moon and full moon." - Merriam-Webster.
The various reasons why spring tides occur are mentioned below:
The forces that contribute to tides are called tidal constituents.
The moon's gravitational pull on the earth is the major tidal constituent.
The greater gravitational force between the objects is close to each other.
The sun and moon both exert gravitational force on the earth.
The moon's pull is stronger than the sun.
Because it is much closer to the earth than the sun.
It exerts a tidal force on the whole earth.
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After the seven days of spring tide, the moon and sun are at right angles to each other. These are known as neap tides. It refers to a period of moderate tides. It has small tides. The meaning of it is that the high tides are a little lower and low tides are a little higher than average. It occurs because the sun and moon pull the water in different directions.
Neap Tide Definition
Some of the recognised and standard definitions are mentioned below:
"It is a tide of minimum range occurring at the first and the third quarters of the moon." - Merriam-Webster.
"either of the two tides that occur at the first or last quarter of the moon when the tide-generating forces of the sun and moon oppose each other and produce the smallest rise and fall in tidal level" - Collins dictionary.
The various reasons why neap tides occur are mentioned below:
When the gravitational pull of the sun is added to the gravitational pull of the moon on earth, it causes the oceans to bulge a bit more.
It occurs during the first and third quarter of the moon when the moon appears "half full."
During the time of full and, the new moon which occurs when the Earth, sun, and moon are nearly in alignment, the range of the tides are slightly larger.
This occurs twice each month.
Spring Tide and Neap Tide
The spring tides have higher high tides and lower low tides whereas neap tides have lower high tides and higher low tides. The difference of the range of the water level between high and low tide is much larger in a spring tide than in a low tide.
Perigean Spring Tide
A Perigean tide occurs when the moon is new or full and either closest to the Earth. The full moon or new moon closely coincides with the perigee of the moon. It occurs often six to eight times a year. These are called Perigean Spring Tides. During the time of perigean spring tide, high tides can be significantly higher than the other times of the year.
Effect of the Perigee
After 28 days, the moon reaches "perigee." It is the closest point of the approach to the Earth. This is the time when the gravitational force of the moon is strong. There will be an increase in the average range of tides during these periods. After that about 14 days, the moon reaches 'apogee'. This is the point where the gravitational force of the moon is weak. At this time of the period, the range of the tides decreases.
Causes of Perigean Spring Tide
The various causes of the occurrence of perigean spring tide are given below:
When the Perigean Spring Tide combined with the seasonal changes in the tide, the sea level may cause little coastal flooding in some low lying areas.
It is referred to as high tide flooding and nuisance flooding.
Main coastal flooding occurs in response to strong onshore winds barometric pressure changes from a coastal storm.
Flooding could be worse if a storm strikes during the perigean spring tide.
Sometimes Perigean Spring Tides have coincided with offshore ocean patterns and large winds that have resulted in highly coastal flooding.
To conclude, we can say that tides are very long-period waves that move through the oceans in response to the force exerted by the moon and the sun. If we talk about the types of tides. They mainly are spring tides and neap tides. "Spring tides" are those tides that occurred at that time when the sun and moon both aligned with the earth. And after the seven days of spring tide, the moon and sun are at right angles to each other. At this time moderate types of tides are produced. These tides are known as "neap tides." Spring tides have higher high tides and lower low tides and on the other hand, the neap tides have higher low tides and lower high tides. There is one more tide which is the type of spring tide, which is called "Perigean Spring Tide". It only occurs when the moon is new or full and either closest to the Earth. High tides can be significantly higher than the other times of the year. It is also known as the "king tide".
We have learned about tide, spring or neap tide, neap tide definition, spring tide definition and causes, and other related aspects. Let's solve some important FAQs: