Meteorology (Weather)/What's the story on "Dodge" tides?
Anna wrote at 2007-06-19 07:11:58
A dodge tide is where there is only one level predicted for the day/stays constant.
Genuine dodge tides are not common but can only be seen in the Bay of Fundy, Nova Scotia, in Canada, the Gulf of California in Mexico and SA gulf waters.
During the neap tide period, the moons gravitational influence slightly excelled that of the sun so there is a lessened tidal range of less than half a metre in our gulf waters. However, when a moon, in its elliptical path around the earth, is that its furthermost point of orbit, (apogee) its gravitational attraction on the sea is weakened because of the increased distance from the earth and just equals the suns pull. The two gravitational influences that are balanced out; there is no resultant pull of the sea surface therefore no tide. The tide has dodged any change
wucka01 wrote at 2007-07-31 04:28:09
there are two places in the world that a dodge tide occurs. south Australia, and in South America in the Gulf of Mexico.
sailorman wrote at 2013-08-04 05:28:50
At full and new moon there are two tidal waves travelling around the planet every day at 1,000mph at the equator, forming regular troughs and crests 6 hours and 6,000 miles apart. At half moon the sun and moon pull at right angles to each other and upset the regularity.
When these tidal waves pass a narrow body of water lying North-South there is not enough time and space for the gravitational pull to have effect. Instead the ocean level at the mouth of the gulf rises so that water runs from this elevated level up the gulf.
During the regular part of the cycle a regular oscillation establishes in the gulf, the high tided at the top of the gulf occurring about three hours later than the tide at the bottom.
At half moon the conflicting gravitational pulls disrupt the regularity and cancel out at least one of the tides. It's like sloshing water in a bath. You can set up a regular pattern, but change the forces involved and the pattern falls apart.
It' not true that the water level doesnt change for a few days; the tides become eratic for a few days, but not unpredictable fortunately
As far as I know dodge tides, apart from the South Australian gulfs occur also in the Gulf of California and the Arabian Gulf, all run North-South off the ocean.