1. Introduction Space-based satellite gravimetry began in the early 1980s when the radar altimeter on board the SEASAT satellite (NASA) was used to measure the marine geoid and its variation globally. Consequently, over the last thirty years, several satellite missions have been carried out by various space organizations for the measurement of the gravitational field and its variations (both in continental and oceanic regions). Initially, altimetry data came from space altimeters such as TOPEX/Poseidon (NASA, CNES) and was used to derive the marine geoid and consequently derive the gravity anomaly. In the last decade, the Gravity Challenging Mini-satellite Payload (CHAMP) and Gravity Recovery and Climate Change Experiment (GRACE) missions have begun to measure the gravity data field directly with methods other than satellite altimetry (Tapley et al., 2004) . These satellites used the idea of satellite-to-satellite tracking (SST) to measure acceleration changes due to gravity (Rummel et al., 2002) and its variations due to changes in lithospheric density. Complete and uniform global coverage was achieved with high accuracy, which allowed the creation of gravity models with higher degrees of spherical harmonics (Reigber et al., 2005a). In addition to this, GRACE, due to its lower repetition cycle, can provide information on the temporal variation of the Earth's gravitational field (Tiwari et al., 2009).2. GOCE: An OverviewThe Gravitational Field and Steady State Ocean Circulation Explorer (hereinafter referred to as GOCE) was launched in March 2009 and is the most sophisticated gravity mission to date. Unlike its predecessors, GOCE uses the concept of satellite gradiometry (Rummel et al., 2002) for the measurement of the gravitational field and its gradients. The GOCE mission was... middle of paper... However, methodology needs to be developed for calculating Bouger anomalies from the data, so that deeper structures on the subcontinent can be identified by their gravitational signatures. At the same time, GOCE data will also open up new venues for studies in other geoscientific fields such as glacier studies, ocean circulation, mass transport and global geoid variations. Finally, data from GOCE, GRACE etc. have now been combined to create global gravitational field models of higher degree/order of spherical harmonics. The International Center for Global Earth Models (ICGEM, http://icgem.gfz-potsdam.de/ICGEM/) has been involved in calculating new gravitational field models by combining satellite tracking, gravity and altimeter data to create high-resolution gravity models (Forste et al., 2012, Goiginger et al., 2011) further refining the image of the Earth's gravity.
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