Terms of Reference

      Accurate determination of the gravity field and its temporal variations is a prime target of modern geodesy. It is closely related to geophysics, geodynamics, navigation, metrology and other related disciplines including the Earth's environmental issues as well. To this end, Commission 2 was established at the IUGG in Sapporo in summer 2003 for promoting, supporting, and stimulating the advancement of knowledge, technology, and international cooperation in the geodetic domain associated with Earth's gravity field. In the last period of 2003-2007, Commission 2 has achieved its primary goals and has been ready for the next quadrennium. Moreover the major part of the associated scientific themes is of long-term interest so that the structure of Commission 2 essentially continues the one in the last period.

      Commission 2, at the start of the new period, consists of four sub-commissions, six projects, two study group and several inter-commission projects, working groups, study groups. The sub-commissions cover following science themes; terrestrial, airborne, ship borne gravimetry and relative/absolute gravity networks; spatial and temporal gravity field and geoid modelling; dedicated satellite gravity missions; and regional geoid determination. The projects are established to organize work on unique and exceptional areas of interest or particular problems requiring specific international cooperation.

      Commission 2 has strong links to sister commissions, ICCT, IGFS and other components of IAG. Connections to these components are created with inter-commission projects, working groups, study groups that provide a cross-disciplinary stimulus for work in several topics of interest to the commission.

      Commission 2 has been expected to involve important problems in the next four years; for instance, analysis of a new type of data from new satellite gravity mission (GOCE); more accurate modelling of the temporal gravity field variation to understand mass transports; new observation technologies. A new Study Group (SG2.2) has been established to look at forward gravity modeling techniques for high-resolution gravity field recovery to assist in processing data from current and future satellite gravity missions. Other Study Groups/ Working Groups focused on well-defined subjects will be established as the need arises.

Objectives

The main objectives of Commission 2 are:

• terrestrial, airborne, ship borne, and satellite gravimetry.

• precise regional and global geoid determination and geopotential modeling.

• regional and global temporal variations in the gravity field.

• dedicated satellite gravity mapping missions.

• gravity determination from satellite altimetry.