Projektbeschreibung
Fortgeschrittene Orientierungsmodelle könnten uns helfen, mit einer noch nie dagewesenen Genauigkeit von weniger als einem Zentimeter zu navigieren
Die Abhängigkeit von der Erdrotation für die Zeitmessung und Navigation ist fortgeschritteneren Technologien wie Atomuhren und GPS gewichen, die eine höhere Präzision bieten. GPS stützt sich auf zwei Bezugsrahmen: den terrestrischen, der relativ zur Erde fixiert ist, und den himmlischen, der im Raum unbeweglich ist. Allerdings können die Umverteilung der Masse und die Anziehungskraft von Sonne und Mond zu Unregelmäßigkeiten in der Rotation und Ausrichtung der Erde führen. Geodätinnen und Geodäten sowie Geophysikerinnen und Geophysiker nutzen Beobachtungen, um diese Veränderungen zu messen, und Verfahren wie Präzession und Nutation, um die Orientierungsmodelle der Erde zu verbessern. Das vom ERC finanzierte Projekt RotaNut wird die Orientierungsmodelle der Erde auf Subzentimeter-Ebene optimieren, indem zusätzliche physikalische Eigenschaften des Planeteninneren und Kopplungsmechanismen an den flüssigen Kerngrenzen identifiziert werden.
Ziel
The rotation of the Earth has long been used as a measure of time, and the stars as reference points to determine travellers’ whereabouts on the globe. Today, precise timescales are provided using atomic clocks and precise positioning is determined using geodetic techniques such as GPS grounded on two reference frames: the terrestrial frame, fixed relative to the Earth and rotating synchronously with the planet, and the celestial frame, which is immobile in space, where the artificial satellites such as those of GPS are moving. The relationship between these frames is complicated by the fact that the rotation and orientation of the Earth is subject to irregularities induced by global mass redistributions with time and external forcing such as the gravitational pull of the Sun and the Moon. With the advance of observation precision, the causes of Earth orientation changes are progressively being identified by geodesists and geophysicists. The term ‘precession’ describes the long-term trend of the orientation of the axis of spin, while ‘nutation’ is the name given to shorter-term periodic variations, which are the prime focus of the present project. The rotation axis of the Earth is moving in space at the level of 1.5km/year due to precession and has periodic variations at the level of 600 meters as seen from space in a plane tangent to the pole. The present observations allow scientists to measure these at the sub-centimetre level enabling them to identify further physics of the Earth’s interior to be taken into account in the Earth orientation models such as the coupling mechanisms at the boundary between the liquid core and the viscoelastic mantle, as well as many other factors (sometimes not yet definitely identified). The proposed research will address many of these and will result in the development of improved global orientation of the Earth with an unprecedented accuracy - at the sub-centimetre level.
Wissenschaftliches Gebiet
- natural sciencesphysical sciencesastronomyobservational astronomyradio astronomy
- natural sciencesphysical sciencesastronomyplanetary sciencesplanets
- natural sciencesphysical sciencesastronomyplanetary sciencesnatural satellites
- natural sciencesearth and related environmental sciencesgeophysics
- natural sciencesmathematicspure mathematicsmathematical analysisdifferential equationspartial differential equations
Programm/Programme
Thema/Themen
Finanzierungsplan
ERC-ADG - Advanced GrantGastgebende Einrichtung
1180 Bruxelles / Brussel
Belgien