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TIDAL DATA ANALYSIS
Mei HandayaniGeodetic Engineering Department, Faculty of Earth
Science and Technology, ITB
[email protected]
In hydrography, tide is variation of sea level due to the
gravity force due to mutual attraction between the earth/moon and
earth/sun
systems. Based on that definition, tidal changes can be
determined and predicted from moon and sun position in the
universe.
However, because of the facts in explanation of ocean and
coastal tidal phenomena changes, tide propagation is vary and
unique in
each location. Below will be analyzed five tidal data in five
different locations in earth. All data were taken in December 2012
for 31
days.
Mona Is. , PR, USA
The highest tidal changes in Mona station occur in day 15 of
December which the flood tide is going into 2757 mm high and the
ebbtide is about 1273 mm high. Based on that data, tidal range in
this station is around 1484 mm high.
Based on the number of high and low tides and their relative
heights each tidal day that can be seen in graph 1 in page before,
this
location experienced two unequal high tides and two unequal low
tides per tidal day. So, this station has mixed semidiurnal tide
of
tidal type.
Praia-C, Cape Verde, Portugal
The highest tidal changes in Praia station occur in day 15 of
December 2012 which the flood tide is 1803 mm high and the ebb tide
is
1103 mm high. Based on that data, tidal range in this station is
around 700 mm high.
Based on the graph 2 in page before, the number of high and low
tides and their relative heights each tidal day, this location
experienced two high tides and two low tides differ in height
per tidal day. In conclusion, this station has mixed semidiurnal
tide of
tidal type.
Fremantle, Australia
The highest tidal changes in Fremantle station occur in day 12
of December 2012 which the flood tide is 1333 mm high and the
ebb
tide is 427 mm high. Based on that data, tidal range in this
station is around 906 mm high.
Based on the graph.3 in page before, the numbers of high and low
tides and their relative heights each tidal day, this location
have
only one high and one low tide each day. In conclusion, this
station has diurnal tide of tidal type.
Colombo-C, Sri Lanka
The highest tidal changes in Colombo station occur in day 14 of
December 2012 which the flood tide is 2110 mm high and the ebb
tide is 140 mm high. Based on that data, tidal range in this
station is around 1970 mm high.
Based on the graph.4 in page before, the numbers of high and low
tides and their relative heights each tidal day, this location
have
nearly two equal tides and nearly two equal low tides each day.
It can be concluded that this station has semidiurnal tidal
type.
Teluk Bayur, Padang, Indonesia
The highest tidal changes in Teluk Bayur station occur in day 13
of December 2012 which the flood tide is 2031 mm high and the
ebb
tide is 1715 mm high. Based on that data, tidal range in this
station is around 369 mm high.
Based on the numbers of high and low tides and their relative
heights each tidal day that can be seen in graph.5 in page before,
this
location only have one high tide and one low tide per tidal day.
So, this station has diurnal tidal type.
Based on each station analysis above, it can be concluded that
each location in earth has its own unique characteristic type of
tidalrange and tidal type. However, the tide itself is influenced
by the depth of ocean, the position of latitude of the presence of
coriolis,
the rotation of earth, seafloor topography, the presence of
land, and others. More depth the ocean, generally it has two high
tide and
two low tide each day because the least of friction with
seafloor. The coastal regions also experienced the larger tide than
the openocean region because tide itself is propagate as shallow
water waves. In hydrography itself, tide is used to depth
reduction, coastal
engineering, scientific research, and marine and coastal
dynamic.
Reference:
Windupranata, Dr. rer nat Wiwin. Tides. Slide Presentation of
Hydrography II. Institut Teknologi Bandung
mailto:[email protected]:[email protected]:[email protected]
