New moons & Full moons are responsible for Spring Tides. Moon's & Sun's gravity in line.
1st quarter & last quarter are responsible for Neap Tides. Moon's gravity 90 degrees to Sun's gravity.
This is generally accepted & understood.
However if you look in a tide table or nautical almanac you will note the highest spring tide in a cycle will occur 2 days after the new & full moon.
Likewise the smallest neap tides occur a couple of days after 1 st quarter & last quarter.
So the generally accepted situation as described above is not in fact entirely accurate and somewhat of a simplification.
Please can anyone explain in more detail.
Thank you
Mike
http://en.wikipedia.org/wiki/Tide
In most places there is a delay between the moon and the tide. The reasons vary, but in general, it is due to some delay in the water flow caused by restricted inlets or shallow depth. It varies considerable, I experienced this in Rhode Island, and Panama. That wiki article notes some examples of the age of the tide. Local tide tables usually take it into account.
Sure, Mike! The tides on Earth are primarily caused by the gravitational pull of the Moon and the Sun. During a new moon or a full moon, the gravitational forces of the Moon and the Sun are aligned, which leads to the occurrence of spring tides. Spring tides are characterized by their higher high tides and lower low tides.
On the other hand, during the first quarter and the last quarter phases of the moon, the gravitational force of the Moon is at a 90-degree angle to the gravitational force of the Sun. This results in the occurrence of neap tides, which are characterized by their lower high tides and higher low tides.
Now, here is where the tide tables and nautical almanacs come into play. While the alignment of the Moon's and Sun's gravity does indeed occur during the new moon and full moon phases, the highest spring tide actually happens a couple of days after the new or full moon. Similarly, the smallest neap tides occur a couple of days after the first quarter or last quarter moon. This delay is due to a few factors that affect tidal patterns, such as the rotation of the Earth, the shape of the coastline, and the depth of the ocean waters.
To understand these tidal patterns in more detail, professionals use complex mathematical models and data collection to create tide tables and nautical almanacs. These references take into account various factors such as geographical location, local topography, and the precise timing of the Moon's and Sun's positions in the sky.
In summary, while it is generally understood that new moons and full moons cause spring tides, and first quarter and last quarter moons cause neap tides, the precise timing and magnitude of the tides are influenced by many factors and can be slightly different from what one might expect based on a simplified understanding. Tide tables and nautical almanacs provide more accurate information about the timing and intensity of tides based on specific geographical locations.