Dynamic sea surface topography is the average difference between the actual surface of the Earth and a geoid. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 The geoid is that Equipotential surface which would coincide exactly with the mean ocean surface of the Earth if the oceans were in equilibrium at rest and extended through It is caused by a steady state ocean current field in the ocean which in turn is caused by climatologic winds and temperature transport in the oceans. An ocean current is continuous directed movement of Ocean water. An ocean (from Greek, ''Okeanos'' (Oceanus) is a major body of saline water, and a principal component of the Hydrosphere. Wind is the flow of Air or other Gases that compose an Atmosphere (including but not limited to the Earth's) The dynamic sea surface topography is usually derived from ship-going measurements of temperature and salinity at depth. A ship /ʃɪp/ is a large vessel that floats on water Ships are generally distinguished from Boats based on size Measurement is the process of estimating the magnitude of some attribute of an object such as its length or weight relative to some standard ( unit of measurement) such as Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature Salinity is the Saltiness or dissolved salt content of a body of Water. In recent years, satellite altimetry systems have made it possible to measure sea surface topography directly. This article is about artificial satellites For natural satellites also known as moons see Natural satellite. An altimeter is an instrument used to measure the Altitude of an object above a fixed level