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Papers by Marta Folgueira

Research paper thumbnail of Analytical computation of total topographic torque at the core–mantle boundary and its impact on tidally driven length-of-day variations

Geophysical Journal International

SUMMARYThe Earth’s rotation exhibits periodic variations as a result of gravitational torques exe... more SUMMARYThe Earth’s rotation exhibits periodic variations as a result of gravitational torques exerted by the Sun and the Moon and of angular momentum exchange of the solid Earth with the Earth’s atmosphere and hydrosphere. Here, we aim at determining the complementary effect of the deep interior on variations in the length-of-day (LOD) and focus on the influence of topography at the core–mantle boundary (CMB). For this purpose, we have developed an analytical approach for solving the Navier–Stokes equation for global rotational motions and inertial waves, based on and extending the approach of Wu & Wahr (1997). An advantage of the analytical approach is that it allows to identify the frequencies and topographic spherical harmonics degrees and orders where resonance can happen, as well as to quantify the total amplifications in the tidal effects on LOD variations. Although the resonances are found to be sometimes quite near tidal frequencies, we show that they are not sufficiently cl...

Research paper thumbnail of Semi-analytical integration of the Earth's precession-nutation based on the GCRS coordinates of the CIP unit vector

Journées Systèmes de Référence Spatio-temporels 2011, Dec 1, 2012

Research paper thumbnail of On the research progress of Descartes-Subproject: "Advances in the integration of the equations of the Earth's rotation in the framework of the new parameters adopted by the IAU 2000 Resolutions

Journées 2005 - systèmes de référence spatio-temporels, Oct 1, 2006

Research paper thumbnail of A new formulation of the damping effect in the Earth's and Mars' freepolar motion

Proceedings of the Journées 2003 "Systèmes deréférence spatio-temporels": Astrometry, Sep 1, 2004

Research paper thumbnail of Discussion on the most adequate sets of variables for the study of the Earth's rotation in the framework of IAU 2000 Resolutions

Research paper thumbnail of Analytical Computation of the Effects of the Core-Mantle Boundary Topography on Tidal Length-Of-Day Variations

Research paper thumbnail of About Orbital and Rotational Changes of (99942) Apophis During the 2029 Close Encounter with the Earth

NEA's constitute a potential threat of collisions with the Earth in the future and in consequ... more NEA's constitute a potential threat of collisions with the Earth in the future and in consequence their study is fundamental. One of the most impressive phenomena related to these objects in the next decades is the close encounter of (99942) Apophis on April 13, 2029. This asteroid, with a diameter estimated at approximatively 300m, will approach the Earth at a distance of roughly 38 300 km from our planet. In this paper we present at first a detailed study of the orbital characteristics of Apophis and their changes during the 2029 encounter. Then we calculate the dramatic rotational effects undergone by the asteroid during the close encounter, depending on a few physical and geometrical parameters.

Research paper thumbnail of The Celestial Frame and the Weighting of the Celestial Pole Offsets in the Computation of VLBI-Based Corrections for the Main Lunisolar Nutation Terms

Sensors (Basel, Switzerland), 2021

Very long baseline interferometry (VLBI) is the only technique in space geodesy that can determin... more Very long baseline interferometry (VLBI) is the only technique in space geodesy that can determine directly the celestial pole offsets (CPO). In this paper, we make use of the CPO derived from global VLBI solutions to estimate empirical corrections to the main lunisolar nutation terms included in the IAU 2006/2000A precession–nutation model. In particular, we pay attention to two factors that affect the estimation of such corrections: the celestial reference frame used in the production of the global VLBI solutions and the stochastic model employed in the least-squares adjustment of the corrections. In both cases, we have found that the choice of these aspects has an effect of a few μas in the estimated corrections.

Research paper thumbnail of Integración numérica del movimiento rotacional libre de un cuerpo rígido

Research paper thumbnail of Novedades culturales y metodológicas en la necrópolis de Herrería (Guadalajara)

Research paper thumbnail of Repercusión de la elasticidad terrestre en el movimiento del polo

Research paper thumbnail of Nutation determination by means of GNSS: status and propects

Research paper thumbnail of Refinements on precession, nutation, and wobble of the Earth

Research paper thumbnail of Recent Advances in Applications of Geodetic VLBI to Geophysics

Information Visualization, 2012

This paper presents recent advances in Earth Orientation Parameters (EOP) determination and in th... more This paper presents recent advances in Earth Orientation Parameters (EOP) determination and in their modeling. These advances are related to the increase of the precision of the observation and the implementation of dedicated strategies to better obtain them. The advances are also related to the determination of Earth geophysical parameters from VLBI observations and better modeling of the phenomena within the Earth. Further improvement in the observation precision enhances our understanding of the interior of the Earth. In particular, we examine the coupling mechanisms at the core-mantle boundary: the electromagnetic coupling, the topographic coupling, and the viscous coupling. We also present future developments necessary for a better understanding of the Earth’s interior and its orientation parameters.

Research paper thumbnail of Earth Rotation: Theoretical aspects, observation of temporal variations and physical interpretation

Research paper thumbnail of Comparison of VLBI-based Luni-solar Nutation Terms

Very Long Baseline Interferometry (VLBI) is the only space geodesy technique that can directly ob... more Very Long Baseline Interferometry (VLBI) is the only space geodesy technique that can directly observe the celestial pole offsets. These values are time-dependent corrections to the IAU200A/2006 precession-nutation model that are estimated by different VLBI analysis centres. The celestial pole offsets, together with the rest of Earth Orientation Parameters (EOP) are combined by the IERS and disseminated in official series.

Research paper thumbnail of Nuevos avances en las teorías de la rotación de la Tierra rígida

Research paper thumbnail of ITRS/GCRS transformation: uncertainty propagation analysis and short-term modelling of IAU 2006/2000A developments

Advances in Space Research, 2018

Research paper thumbnail of Elaboración de estudios para el seguimiento del rendimientoacadémico de los estudiantes de los dobles Grados en Matemáticas

Research paper thumbnail of Estudio arqueoastronómico en la necropolis de Herrería III

Research paper thumbnail of Analytical computation of total topographic torque at the core–mantle boundary and its impact on tidally driven length-of-day variations

Geophysical Journal International

SUMMARYThe Earth’s rotation exhibits periodic variations as a result of gravitational torques exe... more SUMMARYThe Earth’s rotation exhibits periodic variations as a result of gravitational torques exerted by the Sun and the Moon and of angular momentum exchange of the solid Earth with the Earth’s atmosphere and hydrosphere. Here, we aim at determining the complementary effect of the deep interior on variations in the length-of-day (LOD) and focus on the influence of topography at the core–mantle boundary (CMB). For this purpose, we have developed an analytical approach for solving the Navier–Stokes equation for global rotational motions and inertial waves, based on and extending the approach of Wu & Wahr (1997). An advantage of the analytical approach is that it allows to identify the frequencies and topographic spherical harmonics degrees and orders where resonance can happen, as well as to quantify the total amplifications in the tidal effects on LOD variations. Although the resonances are found to be sometimes quite near tidal frequencies, we show that they are not sufficiently cl...

Research paper thumbnail of Semi-analytical integration of the Earth's precession-nutation based on the GCRS coordinates of the CIP unit vector

Journées Systèmes de Référence Spatio-temporels 2011, Dec 1, 2012

Research paper thumbnail of On the research progress of Descartes-Subproject: "Advances in the integration of the equations of the Earth's rotation in the framework of the new parameters adopted by the IAU 2000 Resolutions

Journées 2005 - systèmes de référence spatio-temporels, Oct 1, 2006

Research paper thumbnail of A new formulation of the damping effect in the Earth's and Mars' freepolar motion

Proceedings of the Journées 2003 "Systèmes deréférence spatio-temporels": Astrometry, Sep 1, 2004

Research paper thumbnail of Discussion on the most adequate sets of variables for the study of the Earth's rotation in the framework of IAU 2000 Resolutions

Research paper thumbnail of Analytical Computation of the Effects of the Core-Mantle Boundary Topography on Tidal Length-Of-Day Variations

Research paper thumbnail of About Orbital and Rotational Changes of (99942) Apophis During the 2029 Close Encounter with the Earth

NEA's constitute a potential threat of collisions with the Earth in the future and in consequ... more NEA's constitute a potential threat of collisions with the Earth in the future and in consequence their study is fundamental. One of the most impressive phenomena related to these objects in the next decades is the close encounter of (99942) Apophis on April 13, 2029. This asteroid, with a diameter estimated at approximatively 300m, will approach the Earth at a distance of roughly 38 300 km from our planet. In this paper we present at first a detailed study of the orbital characteristics of Apophis and their changes during the 2029 encounter. Then we calculate the dramatic rotational effects undergone by the asteroid during the close encounter, depending on a few physical and geometrical parameters.

Research paper thumbnail of The Celestial Frame and the Weighting of the Celestial Pole Offsets in the Computation of VLBI-Based Corrections for the Main Lunisolar Nutation Terms

Sensors (Basel, Switzerland), 2021

Very long baseline interferometry (VLBI) is the only technique in space geodesy that can determin... more Very long baseline interferometry (VLBI) is the only technique in space geodesy that can determine directly the celestial pole offsets (CPO). In this paper, we make use of the CPO derived from global VLBI solutions to estimate empirical corrections to the main lunisolar nutation terms included in the IAU 2006/2000A precession–nutation model. In particular, we pay attention to two factors that affect the estimation of such corrections: the celestial reference frame used in the production of the global VLBI solutions and the stochastic model employed in the least-squares adjustment of the corrections. In both cases, we have found that the choice of these aspects has an effect of a few μas in the estimated corrections.

Research paper thumbnail of Integración numérica del movimiento rotacional libre de un cuerpo rígido

Research paper thumbnail of Novedades culturales y metodológicas en la necrópolis de Herrería (Guadalajara)

Research paper thumbnail of Repercusión de la elasticidad terrestre en el movimiento del polo

Research paper thumbnail of Nutation determination by means of GNSS: status and propects

Research paper thumbnail of Refinements on precession, nutation, and wobble of the Earth

Research paper thumbnail of Recent Advances in Applications of Geodetic VLBI to Geophysics

Information Visualization, 2012

This paper presents recent advances in Earth Orientation Parameters (EOP) determination and in th... more This paper presents recent advances in Earth Orientation Parameters (EOP) determination and in their modeling. These advances are related to the increase of the precision of the observation and the implementation of dedicated strategies to better obtain them. The advances are also related to the determination of Earth geophysical parameters from VLBI observations and better modeling of the phenomena within the Earth. Further improvement in the observation precision enhances our understanding of the interior of the Earth. In particular, we examine the coupling mechanisms at the core-mantle boundary: the electromagnetic coupling, the topographic coupling, and the viscous coupling. We also present future developments necessary for a better understanding of the Earth’s interior and its orientation parameters.

Research paper thumbnail of Earth Rotation: Theoretical aspects, observation of temporal variations and physical interpretation

Research paper thumbnail of Comparison of VLBI-based Luni-solar Nutation Terms

Very Long Baseline Interferometry (VLBI) is the only space geodesy technique that can directly ob... more Very Long Baseline Interferometry (VLBI) is the only space geodesy technique that can directly observe the celestial pole offsets. These values are time-dependent corrections to the IAU200A/2006 precession-nutation model that are estimated by different VLBI analysis centres. The celestial pole offsets, together with the rest of Earth Orientation Parameters (EOP) are combined by the IERS and disseminated in official series.

Research paper thumbnail of Nuevos avances en las teorías de la rotación de la Tierra rígida

Research paper thumbnail of ITRS/GCRS transformation: uncertainty propagation analysis and short-term modelling of IAU 2006/2000A developments

Advances in Space Research, 2018

Research paper thumbnail of Elaboración de estudios para el seguimiento del rendimientoacadémico de los estudiantes de los dobles Grados en Matemáticas

Research paper thumbnail of Estudio arqueoastronómico en la necropolis de Herrería III

Research paper thumbnail of Impact of tidal Poisson terms on nonrigid Earth rotation

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