Rsbm for brevity
"Note that the night of Sunday 19th June 1988 low tide was at 9.00 pm (Fremantle) and high tide was at 11.23 am on the 20th June 1988.
The tide rose around 40 cm in 14 hours.
On the morning the car was discovered the tide was also coming in.
Low tide was 9.00 pm on the 21st June and high tide 9.30 am on the 22nd June 1988. The tide rose around 25 cm in 12 hours."
Gee thats a small tidal change prediction..
So small that i can't understand what you think a miniature tide level change is going to do ? Especially with the high tides between 9:30am & 11:30am , any tyre tracks would therefore be seen early in morning before the tide came up the beach the furthest high tide mark..
Can you explain more clearly how it affects anything ?
You will find that those levels also are Wrong due to the "inverse barometer effect" !
You'll find that the tide would be lower than predicted due to high barometric pressure.
Adjustments need to be made to correctly state the tide at the time ..
Along with the well known gravitational effects of the moon sun and other planets, there's one more lesser known but major contributing factor to the current sea level.
That being the atmospheric air pressure.
The atmosphere is constantly exerting pressure down on the Earth and ocean, with one cubic meter of air at sea level weighing about one kilogram.
The constantly changing weather along with high and low pressure cells moving over us has a greater effect on the tidal range than you'd first think.
For every 10hPa change in surface air pressure, a change of 10cm is seen at sea level.
When low pressure systems move over a region the sea level rises by a relative amount , while high pressure systems push down on the ocean creating a drop in sea level .
This is called the inverse barometer effect, as the higher the pressure the lower the sea level , and vice versa.
It should be noted that the sea level doesn't change instantaneously but more so responds to the average change in pressure over a larger area.
In general changes in surface pressure are in the vicinity of 20-30hPa and in turn the sea level doesn't change more than 20-30cm (except for storm surge / coastal inundation).
Global weather models assume an average Mean Sea Level Pressure of 1013hPa, so when the pressure varies from this we see the inverse barometer effect modifying the actual tidal heights and this modification is usually noted as a residual.
All around the country tidal observation sites show the forecast tide heights and the residual tide level.
Quote from the article below :
"An inverted barometric correction is necessary to use the sea level data for ocean dynamics research. We use NCEP sea surface atmospheric pressure for this correction, that is, with every 1 mb increase of air pressure, the sea level is increased by 1 cm.
The inverted barometric correction increases the Fremantle sea level annual variation range but reduces its interannual variability. Before correction, the Fremantle sea level deviation has an annual variation range of about 19 cm and reaches its peak value during June. The sea level atmospheric pressure has an annual range of about 6 cm and is highest during the late winter of July-September. After the inverted barometric correction, the annual range of sea level variation increases to 23 cm, still peaking in June. That is, the atmospheric correction increases the annual range of sea level deviation by about 20%.**Also note that the sea level standard deviations after the inverted barometric correction are smaller than those before the correction during most months. This is due to the inversed relationship between the atmospheric pressure in Fremantle and the SOI on the interannual time scale."
http://www.per.marine.csiro.au/staff/Ming.Feng/Climate_impact2.htm
