Neap Tides Definition | Neap Tides Moon Phase | Neap Tides Diagram
Neap Tides Definition
What is Neap Tide?
A neap tide is a name for a tide in certain coastal regions when the difference between high and low water is at its least. Neap tides are the kind of tides that occur when the moon is at a 90-degree angle from the sun. The neap tide occurs between spring tides, during which the difference between high and low water is greatest.
Unlike spring tides, neap tides are not predictable according to any scientifically measured cycles. Neap tides occur throughout the world in all seas and oceans but are most common around equinoxes or solstices.
A neap tide occurs when there is a new or full moon (the phases most closely associated with tides). The gravitational forces acting on the Earth’s oceans are then balanced. The Sun and Moon pull in the same direction, although not with equal force.
As a result, at low tide, there will be areas that experience lower high-water levels than normal. These are called “neap” tides and can be calculated as being half a degree less than average.
Neap Tides Moon Phase
Theoretically, there are two high tides during a neap tide cycle, but in practice, the second high tide may be so close to the average that it is indistinguishable. The time between successive low waters will be longer than average, and similarly for successive high waters.
Neap tides Example
What is an example of a neap tide?
In the United Kingdom, neap tides normally occur around the time of the winter (Southern Hemisphere) and summer (Northern Hemisphere) solstices. Neaps are also common around equinoxes. For example, there are two neaps per year during March and September at the latitude of London.
For the same reason, the term “neap tide” is also applied to a similar phenomenon occurring under other conditions (such as a spring tide in late autumn or early winter and a neap tide in late spring). In general, it is known as “spring tend,” “spring freshet,” or simply “freshet.”
In coastal areas with a pronounced tidal range, neaps are characterized by higher tides than during the corresponding periods of a spring tide, when the Sun and Moon pull in opposite directions. Neaps can be characterized as “small springs” or “little neaps.”
A neap tide occurred on 11 October 2009; its maximum range was recorded at Newlyn in the UK at, while the minimum range occurred at Brittany (Finistère). The largest neaps and smallest springs are usually recorded in the English Channel, where the tidal range is similar to that of the Atlantic Ocean.
Because the Sun and Moon pull in opposite directions during a neap tide, a high tide is followed approximately six hours later by a smaller low tide. This phenomenon can confuse those who are unaware of it, so when low tide is due, they may stand on “dry land” waiting for it to arrive with no water appearing around their ankles. They may even try to retrieve their belongings from the sea only to find they are ankle-deep.
The phenomenon is also sometimes referred to as a “big-spring” or “big-neap” tide. It is actually more accurately described as a “small spring,” with the opposite of a spring tide (a neap) occurring during that period. The term “small spring” has been adopted by many in Britain, especially in Cornwall, where it occurs due to the Cornish coastline’s characteristic serpentine shape.
Length of neap tide
The length of neap tide observed at a particular location at any given time depends on the phase of the Moon. Tides are always longer during a full moon and shorter during a new moon. In the Northern hemisphere, this tide is called a “neap” because it “shortens” (is shorter than average) for about half of each month.
In the Southern hemisphere, it is called a “spring” tide in New Zealand because it “lengthens” (is longer than average) for a similar period of time.
In certain coastal areas, there are spring tides and neap tides that occur under the influence of tidal inlets or straits.
For example, an extreme example occurs at St. John’s Harbour in Newfoundland, where the water level rises by as much as and falls by over the 9:50 a.m.–10 p.m. tidal cycle. Whereas the average range of a spring tide is about, this particular one reaches over twice that, and it can at times peak over.
Tides may sometimes be predicted accurately by astronomical calculation. The precession of the equinoxes (the apparent rotation of the Earth’s poles) also plays a part in determining neaps.
The closest approach of the Sun to an equinox occurs during spring tides when there is an excess of high tides; when it approaches its minimum distance during neap tides, there is a deficit.
The Moon follows a similar path, but its low tides do not normally reach zero. When the Sun and Moon are at their closest point during an equinox, the tidal force they exert on each other is at its greatest, resulting in a larger tidal range.
The two annual neap tides in London occur because the Earth’s rotational axis is tilted approximately 23 degrees with respect to its orbit around the sun (an axial tilt of 23.44 degrees). In London, the Sun is at a maximum altitude of 18.5 degrees at the summer solstice and at a minimum of −18.5 degrees at the winter solstice.
The time of year when neap tides occur also depends on one’s geographic location. In areas such as the UK, neap tides are likely to occur for about six weeks around each equinox and for about six weeks around each solstice.
Why do Neap Tides Occur?
When a neap tide occurs, the water is actually higher on either side of the line that separates the two sides. This happens for two reasons. The first is due to gravitational forces. The second is because the Earth rotates on its axis, which causes the high and low tides to be in opposite positions than they ordinarily would be.
Neap Tides Diagram
Neap tide diagram shows the bulge of the ocean caused by the sun partially cancels out the bulge of the ocean caused by the moon. This produces moderate tides known as neap tides, meaning that high tides are a little lower and low tides are a little higher than average.
Importance of Neap Tides
As the Neap tide occurs at the lowest point in each lunar month, it can be used for a variety of different purposes.
In Japan, there is a neap tide festival held on the third Saturday in April every year. The festival began in 1959 on Oki Island near Tokyo and has since spread to several other western Japan areas. It is held to commemorate the return of a group of Japanese families who were exiled to Hawaii during World War II. The festival includes music and performances as well as the consumption of neap tide foods.
In the United Kingdom, there is a Neap Tide Festival held annually on the Saturday closest to the full moon in September. The festival is run by the British Neap Tide Society and was established in 1995. It is held at several locations, including Reading, Bridgwater, St Ives, Corfe Castle, Itchenor near Newbury, Taunton, and other locations around the country.
The Penlee Lifeboat Museum, a museum in Penzance, Cornwall, also hosts an annual neap tide festival. The festival takes place at the museum on the third Saturday of September every year and is held to commemorate the lifeboatmen who have lost their lives in service.
Scientists often use the neap tide to predict when an incoming storm will be at its weakest. The neap tide will come about fifteen to twenty-four hours before the storm is projected to arrive. Most people are already aware of the dangers of storms, especially if they live in an area that is prone to hurricanes and other natural
Spring Tides and Neap Tides
Difference between Spring tides and neap tides
Spring Tides |
Neap Tides |
| Spring tides occur when the Earth, Sun, and Moon are aligned.
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Neap tides occur when the Earth, Sun, and Moon are at right angles to each other.
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| Spring tides occur when the moon is either new or full | Neap tides are smaller in amplitude and happen during the first and last quarters of the moon’s cycle |
Note:
The gravitational forces of these three bodies create a tide that is higher than average during spring tides, while neap tides have lower-than-average tidal ranges.
The difference between spring tides and neap tides is that the spring tide’s high water range is greater than its low water, whereas the neap tide’s range of high water is lower than its low water.
Spring Tides and Neap Tides Diagram
The difference between spring and neap tides can be seen by looking at their respective tidal curves
.