Sea inward which in turn creates the

Sea surface topography and satellite altimetryAltimetry is a technique which measures height and it can be used in sea surface to measure the topography of oceans. Satellites from outer space can be sued to map sea surface topographies. One of the first satellite that allowed scientist to map ocean topography was TOPEX/ Poseidon satellite which has been sued to calculate sea level rise and properties such as ocean heat storage. Sea surface is not smooth or calm as it appears generally in nature. Over time scale, sea surface is influenced by ocean circulation, tidal forces of the moon and sun acting on earth, changes in salinity, temperature, waves etc. The ocean surface lumps outward and inward which in turn creates the topography of the ocean floor. These lumps in ocean surface are hard to catch with human eye, however they can be measured using a radar altimeter in a satellite. (Topex, ucsd. edu, 2017) Geosat and (European Space Agency) ERS 1 satellite are examples which can conduct this using the radar on board. They can allocate the cause of ocean surface bulging outward and inward, and can also measure how big these bumps are. These lumps and slopes in the geoid height can be measured from satellite by means of an accurate radar. (Topex,ucsd. edu, 2017) For example, in 1985, US Navy launched the Geo eye satellite to map the geoid height at a horizontal resolution of 10-15 km with a vertical resolution of 0.03 m (1 in). The satellite known as Geosat was released in the polar orbital regions in order to gain high latitude range (+- 72 degree latitude). (Topex, ucsd. edu, 2017) This polar orbital satellite is able to circle the earth at least 14 times a day because of its very fast speed of rotation of 7 km/s. (Topex, ucsd. edu, 2017) The earth rotates under the fixed platform of the satellite orbit, and over a period of 1.5 years, the satellite plots the geographic features of earth surface with a horizontal range of about 6 km in ground level . (Sandwell, 1990)Source : ( Sandwell , 2006)Figure : It shows a flowchart of satellite communication with land and scanning sea surface topography from top. Satellite altimeter can also be used to explore petroleum at the sea to locate offshore sedimentary basins in remote areas. Apart from these, satellite altimetry data are used in general to understand or track weather patterns, navigation routes, fisheries management etc. Observations made from top are used to study ocean currents, heat content of currents and most recently, it is being used to estimate the changes in sea level. (Stewart , 2008)