Space geodesy: Sensing changes on the Earth system

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crustal deformation Earth rotation gravitational field observation techniques space geodesy

Learning objectives

Many physical processes within the solid Earth, the atmosphere, the oceans, the continental water, and the ice sheets, produce small variations of the Earth’s shape, its rotation and its gravity field. Improving our understanding of these processes and their interactions is fundamental for understanding the Earth system and, in particular, the threats to society from geohazards and climate change. Space geodesy emerges nowadays as an indispensable science for the understanding of the Earth system.

This unit includes a comprehensive review of the current state-of-the-art observations from several complementary space geodetic techniques, including Global Navigation Satellite Systems (such as GPS and Galileo), laser and Doppler ranging, radio-telescopes and gravimetry. The student will acquire the necessary knowledge for the interpretation of subtle changes on fundamental Earth processes through research carried out internationally with these observing techniques: their use, their capabilities, but also their limitations.


Basic knowledge in mathematics and physics.

Brief description of the course

Introduction to space geodesy: overview of space geodetic science, the goals, the historical context and evolution of the observation techniques.

Earth’s crustal deformation: overview of the most precise observations of present-day Earth deformation at different temporal and spatial scales.

Earth’s rotation changes: overview of historical and modern observations of Earth’s rotation variations, their known causes and their links with geophysical processes.

Earth’s reference frames: overview of the different geodetic reference frames and their use in Earth sciences.

Earth’s gravity field changes: overview of the observations of changes in the Earth’s gravity field from space.

Earth’s geocenter and dynamical oblateness changes: overview of the impact of fluid mass redistributions on the geocenter motion and the Earth’s shape.