terms of reference

Objectives

Knowledge of the gravity field in space and its temporal variations is of prime importance for geodesy, navigation, geophysics, geodynamics, and related disciplines. Efficient and accurate modeling of the field spans a broad spectrum of activities that utilize data from ground, airborne, and satellite systems. An important subset of these modeling efforts includes the precise determination of the geoid for applications ranging from traditional height systems to oceanography.

Commission 2 (the Gravity Field Commission), of the International Association of Geodesy is concerned with promoting, supporting, and stimulating the advancement of knowledge, technology, and international cooperation in the geodetic domain associated with Earth’s gravity field. This domain comprises several major themes of long-term interest, each under the purview of a sub-commission. The themes cover terrestrial, airborne, shipborne, and satellite gravimetry; terrestrial relative and absolute gravity networks; precise regional and global geoid determination and geopotential modeling; topographic/isostatic modeling; regional and global temporal variations in the gravity field; dedicated satellite gravity mapping missions; and gravity determination from satellite altimetry.

The Gravity Field Commission essentially continues the work of the former Section III of the IAG (Determination of the Gravity Field), but includes some aspects of satellite geodesy (former Section II), and is designed to have stronger links to other components of the IAG, specifically the Inter-Commission Committee on Theory (ICCT) and Commission 1 (Reference Frames). The sub-commissions cover the major themes listed above, which constitute the principal areas in gravity field modeling, determination, and measurement technology, as well as the specific problems and activities related to regional geoid determination. Study Groups, as under the former structure, continue to look at well-defined subjects over shorter duration. They are placed under the sub-commissions. Projects are established under the Commission to organize work on unique and exceptional areas of interest or particular problems requiring specific international cooperation. The regional geoid determination projects, being of paramount importance, are collected under the Sub-commission 2.4, in order to provide close links between them. Connections to other components of the IAG are created with inter-commission working groups that provide a cross-disciplinary stimulus for work in several topics of interest to the Commission. Finally, the Commission has very strong links to several of the Services in geodesy, particularly the newly established International Gravity Field Service and its component services.

Program of Activities

The Gravity Field Commission fosters and encourages research in the areas of its sub-entities by facilitating the exchange of information and organizing Symposia, either independently or at major conferences in geodesy. The activities of its sub-entities, as described on this Internet site, constitute the activities of the Commission, which will be coordinated by the Commission and summarized in annual reports to the IAG Bureau.

In this modern age of instant change, enabled by electronic forms of information exchange, it is only natural that the structure of Commission 2, its membership, and its connection to other components of the IAG has a dynamic character that will evolve over the current term between IUGG General Assemblies. In fact, this evolution is necessary as the new structure of the IAG takes shape and re-establishes and re-defines its purview over regional and international geodetic activities. The current status of Commission 2, including its structure and membership, as well as links to the internet sites of its sub-entities and parent and sister organizations and services, will be updated regularly and can be viewed on this site.