Over the past years significant progress has been made in the advancement of geodetic observation systems that resulted in largely improved accuracies of parameters related to the Earth's rotational motion and its variability. In this session we seek contributions in the following areas:
We are interested in the progress of theories of Earth rotation. We seek contributions on theoretical developments that are consistent internally and with the highly accurate observations at the mm-level, to meet the requirements of the IAG's Global Geodetic Observing System (GGOS). In particular, we invite presentations that address questions raised in the final report of the IAU/IAG joint working group, 'Theory of Earth Rotation and Validation'.
With respect to geodetic and astrometric observational techniques, we seek contributions that highlight new determinations of Earth Rotation Parameters (EOP) series and their analyses, including combinations of different observing techniques.
We also invite discussions of both the dynamical basis for links between Earth rotation, geophysical fluids, and other geodetic quantities, such as the Earth gravity field or surface deformation, and also of investigations leading to more detailed explanations for the physical excitations of Earth rotation.
Besides tidal influences from outside the Earth, the principal causes for variable EOP appear to be related to the changing motions and mass redistribution of the fluid portions of the planet due to angular momentum exchange. Observations of the geophysical fluids (e.g., atmosphere, oceans) have achieved a new maturity in recent years. Independent observations include the results of recent gravity missions like GRACE.
We also welcome contributions about the relationship between EOP variability and current or potential variability in fluids due to climate variation or global change signals. Besides contemporary determination of the EOP and the related geophysical excitations, forecasts of these quantities are important especially for the operational determination of Earth orientation, e.g., for spacecraft navigation; the effort to improve predictions currently is a topic of strong interest. In this sense, the session is also open to contributions dealing with the operative use of Earth orientation in different applications.
In addition, we will welcome input on the modeling, characteristics, variability, and excitations of the rotation parameters of other planets or planetary bodies.