Gravity, as we know changes with alterations in mass, and therefore contains information on mass changes within and on the surface of the earth. The changes in mass at any given location and time happens continuously with the atmospheric circulation, ocean currents, river flow, groundwater extraction, precipitation and glacier melting. Measuring gravity, called gravimetry, has been in practice for more than two centuries for determining physically meaningful heights, in determining water flow and mineral exploration. With recent advances in gravimetry, especially gravimetry using space-borne platforms, it has been possible to measure the variations of the gravity field of earth in time.

The Gravity Recovery and Climate Experiment (GRACE) satellite mission, launched in 2002, and its successor GRACE Follow-On (GRACE-FO), launched in 2018, observe the temporal variations in gravity. They have enabled us to measure the total water storage available on land, the amount of ice mass lost to the oceans and the rise in sea-level. They have been contributing immensely to climate change studies, and enabling greater understanding of the Earth system. However, the applicability of GRACE(-FO) data is limited to studying variations over large regions. Given the potential of the data for a wide array of geoscience research themes, a number of efforts in terms of algorithms, mission design concepts and instrumentation are being taken to widen its applicability for smaller regions. It is slowly becoming a multi-national effort wherein space agencies of different countries are planning to launch satellite gravimetry missions to improve the current capabilities.

In this context, an online workshop titled The present and future of satellite gravimetry was conducted at IIT Kanpur to invigorate satellite gravimetry research in India, and join the global endeavour of launching a satellite gravimetry mission. Given the long-standing expertise and contribution of the Indian Space Research Organization (ISRO) to earth observation, India is well placed to join this endeavour. In this workshop, researchers at the forefront of satellite gravimetry research, ISRO, IITs and NITs were invited and the synergies and collaborations for developing a future Indian satellite gravimetry mission were deliberated. The workshop included 21 oral presentations spread over two days in three themes – Initiatives and programmatics; Mission design; and Satellite gravimetry applications. The workshop had participants from Germany, The Netherlands, USA, Denmark, Australia and Iran.

The workshop was inaugurated by Dr. K. Radhakrishnan, Chairman, Board of Governors, IIT Kanpur, ex-Chairman, ISRO. It was followed up with welcome speeches from Prof. Abhay Karandikar, Director, IIT Kanpur, Prof. S.N. Tripathi, Head of the Department, Civil Engineering and Prof. B. Nagarajan, Chairman, National Geodesy Programme. The workshop ended with a group discussion to chart an action plan for the future, and it was unanimously agreed to conduct a follow-up workshop in 2021.

For further details on the workshop, please visit
https://satgrav2020.tuxfamily.org/

The workshop was organized by Profs. Balaji Devaraju (IIT Kanpur) and Nico Sneeuw (University of Stuttgart) under the aegis of the National Centre for Geodesy (NCG), (coordinated by Prof. Onkar Dikshit, IIT Kanpur) and the National Geodesy Programme (NGP) (chaired by Prof. B. Nagarajan, IIT Kanpur). NCG is a centre of excellence established by the Department of Science and Technology (DST), Government of India (GoI) at IIT Kanpur in 2019 to rejuvenate geodesy education and research in India. NGP is an overarching programme established by the DST, GoI to oversee geodetic activities in the country and provide recommendations for its growth.

For further details on NCG please visit: https://iitk.ac.in/ncg/