Tides are the gradual rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth.
Tides are an entirely separate phenomena than waves caused by wind or tsunamis caused by under-sea earthquakes, volcanic eruptions or landslides. Tides, unlike waves, are predictable months or years in advance. Tide tables, graphs and tide calendars are available from many print and online sources.
Basically, tides are very long-period waves that move through the oceans in response to the forces exerted by the moon and sun. Tides originate in the oceans and progress toward the coastlines where they appear as the regular rise and fall of the sea surface. When the highest part, or crest of the wave reaches a particular location, high tide occurs; low tide corresponds to the lowest part of the wave, or its trough.
The difference in height between the high tide and the low tide is called the tidal range. A horizontal movement of water often accompanies the rising and falling of the tide. This is called the tidal current.
The incoming tide along the coast and into the bays and estuaries is called a flood current or flood tide ; the outgoing tide is called an ebb current or ebb tide. The strongest flood and ebb currents usually occur before or near the time of the high and low tides.
The weakest currents occur between the flood and ebb currents and are called slack tides. When the sun, moon are in line with the earth earth you can expect the highest and lowest tides. Spring tides occur at the time of a full moon. During this period the high tide will be higher and the low tide lower than average.
A King Tide, is a colloquial term for an especially high spring tide. The use of the term "king tide" originated in Australia, New Zealand and other Pacific nations to refer to an especially high tide that occurs only a few times per year. The term is now used in North America as well, particularly in low-lying South Florida, where they cause sunny day tidal flooding.
King tides occur because of the combined influence of a number of astronomical factors related to the Sun and the Moon, and their alignments relative to Earth. When king tides occur during cyclones, floods or storms, water levels can rise to higher levels and have the potential to cause great damage to property and the coastline. During normal weather conditions the height of the king tides will be similar from year to year. A Neap tide will occur after the first and last quarter of the lunar month.
During this period the high tide is lower than usual and the low tides are higher than usual. The strongest flood and ebb currents usually occur before or near the time of the high and low tides.
The weakest currents occur between the flood and ebb currents and are called slack tides. In the open ocean tidal currents are relatively weak. Near estuary entrances, narrow straits and inlets, the speed of tidal currents can reach up to several kilometers per hour Ross, D.
Tides and Water Levels What are Tides? I'm sure someone else could help you out here. Just remeber those age old rules, no run no fun and no flow no go! Cheers, Mitch. To answer your other question, the water flows faster on the 'outside' of the bends of a river which is generally the deeper section. True, but it's only deeper because the tide flow is faster and not vice versa. The middle 2 hrs of the tide is the fastest and the speed is determined by how far the tide has to travel in similar times ie.
Can't be bothered doing the maths now, but that's the basic manner of calculating Mate, Just remeber those age old rules, no run no fun and no flow no go! Generally yes, but certain areas of the bay produce better at top or bottom of tide when the flow is usually very strong at other times. Curtin for example, and on king tides, the beacons also, at least in my experience. To clarify the rule of 12ths This is an approximating method used for calculating the depth of water at a particular position where a shallow area exists and you need to know if it can be safely passed in your vessel at a particular point in time during the tidal period.
Look up the tide chart and get the lowest tide for the period and the change in height for the tide.
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