Assignment title: Write a short note on your best understand term in todays lecture ( Tidal Correction Lecture -3)
I understand the term “Tidal Correction” which is under “Gravity method”. Now I am giving a short note about this topic.
Gravity: It’s a natural phenomenon which invisible force pulls object toward each other. Earth’s gravity is what keeps us on the ground and what make things fall. Any objects that has mass also has the gravity including planets, stars, galaxies, even light.
FIGURE: Gravity between the Earth and the Moon
Gravity method: The gravity method depends on the natural gravimetric field of the Earth and Newton’s law of gravity. This method may be applied for elevation correction, topography, tidal correction, latitude correction, instrumental drift correction and so on.
Tides: Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and rotation of the Earth. Tide tables are used by locals to find the predicted times and amplitude.In1920, an engineer by name of ‘Dexter Cooper’ came up the idea of creating power of tides. There are four types of tides. They are:
- Diurnal tide: It’s a cycle which experience one high tide and one low tide in every lunar day.
- Semi diurnal tide: It’s a cycle which experience two high tide and two low tide in every lunar day.
- Mixed tide: It has two high tide and two low tide per day but height of each tide is different.
- Meteorological tide: It represent all atmospherically influenced tides such as storm surges.
Tidal correction: A correction made in gravity observations to remove the effect of the Earth’s tides. It has smaller mass, the gravitational attraction of the Moon is larger than that of the Sun because of it’s proximity. Actually, the periodic gravity variations caused by the combined effects of the Sun and the Moon are known as tidal variations.
The lunar tidal acceleration at the Earth’s surface along the Moon-Earth axis is about 1.110-2 g, the solar tidal acceleration at the Earth’s surface along the Sun-Earth axis is about 0.5210-7 g where g is the gravitational acceleration at the Earth’s surface. The formula of the ‘Tidal Force’ is
There are three types of tidal force. They are:
- The effects of Centrifugal Force.
- The effects of Gravitational Force.
- The Net or Differential Tide –Raising Force.
Importance of tides:
- It create the oceanic tide of the Earth’s oceans.
- It improve the accuracy of satellite which used in coastal areas.
- It’s mainly affect marine ecosystem.
- It influence the kinds of plants and animals that thrive in what is known as the intertidal zone.
- The area between high tide and low tide, many shorelines, tided from tide pools.
- It’s not only destroy but also help in the formation of creeks and inlets.
- In coastal area, locals trap water during high tides which is used for the manufacturing of salt.
- It helps fisherman and local people by navigation, recreation and coastal development.