Geodesy is a branch of geophysics that studies the geometrical, structural, and gravitational properties of the Earth,their time evolution, and the dynamic interactions of the solid Earth with other physical components of the Earth system(atmosphere, hydrosphere, cryosphere, and the core), at a wide range of temporal and spatial scales. Geodesistsalso study the corresponding topics for other planets in the solar system.
Observations and measurements are at the heart of geodesy. Measurements of the static Earth aimed at understanding its size, shape, and motion have been made for many centuries, earning geodesy the sobriquet of “oldest Earth science.” In the last half-century, space techniques using extraterrestrial components and measurements have revolutionized the research and applications of geodesy, hence the term “space geodesy.” Space geodetic observations are used today to measure global, regional, and local crustal deformation and gravity variability associated with a wide variety of geophysical processes; to investigate mass motions inherent in the global water cycle; to monitor atmospheric water vapor and temperature; to study the dynamics and kinematics of glaciers and ice sheets; and to study changes in the planet’s moment of inertia and rotation. Due to the wide application of space geodetic observations, space geodesy has today become the most interdisciplinary branch in all of the geophysics.
AGU’s Geodesy Section is proud to contribute to this heritage over the decades, in providing services and fostering interactions among geodesists as well as between colleagues in other disciplines.