neap tides

Spring tides have higher high tides and lower low tides whereas neap tides have lower high tides and higher low tides. Hence, the range (difference in water level between high and low tide) is much larger in a spring tide than in a low tide.

Rather, the term is derived from the concept of the tide “springing forth.” Spring tides occur twice each lunar month all year long without regard to the season. Neap tides, which also occur twice a month, happen when the sun and moon are at right angles to each other.

Because the Earth rotates through two tidal “bulges” every lunar day, coastal areas experience two high and two low tides every 24 hours and 50 minutes. This occurs because the moon revolves around the Earth in the same direction that the Earth is rotating on its axis.

At the coast, low tide is the time when the sea is at its lowest level because the tide is out.

It does not rise only at night. Actually the moon is in the sky during the day just as long as it is in the sky during the night, it’s only that it’s very difficult to see it during the day because the Sun is too bright in comparison. And thus, tidal waves rise as much during the night as they do during the day.

While older tidal measuring stations used mechanical floats and recorders, a new generation of monitoring stations uses advanced acoustics and electronics. In addition to measuring tidal heights more accurately, the new system also records 11 different oceanographic and meteorological parameters.

An efficient way of guesstimating how much water there is, at any given time of day, over a particular point. The rule of twelfths works like this; take the difference in height between the high and low tide on that day, and divide that by 12 equal chunks.

Tides affect other aspects of oceanic life, including the reproductive activities of fish and ocean plants. Floating plants and animals ride the tidal currents between the breeding areas and deeper waters. The tides help remove pollutants and circulate nutrients ocean plants and animals need to survive.

At any given time of day, the tide is either slowly moving in or moving out. One indirect but very powerful affect tides have on humans is in the behavior of sea life. Even fish that do not act based on tidal movements are still part of the food chain that is supported by the constant tidal cycles.

Predicting tides has always been important to people who look to the sea for their livelihood. Commercial and recreational fishermen use their knowledge of the tides and tidal currents to help them improve their catches. In some areas, strong tidal currents concentrate bait and smaller fish, attracting larger fish.

A tide table becomes a major point of reference when a vessel tries to enter an inlet or a bay or an estuary for the purpose of docking. In water-parts like these, the presence of a low tide will moor the vessel even before it can dock at the dockyard and a high tide will disallow a vessel to dock at the required area.