Article
Geochemistry & Geophysics
Hao Ding, Yachong An, Wenbin Shen
Summary: Research suggests that there have been no stable damping trends in the SYO and EYO intradecadal oscillations since 1962. While there may be some relationship between the SYO/EYO and geomagnetic jerks, there is no particular consistency between them, and the EYO does not seem to be helpful in predicting jerks.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Bai ChunHua, Kang GuoFa, Gao GuoMing, Wen LiMin, Sun YuanPeng
Summary: Investigating the relationship between geomagnetic jerks and the geomagnetic secular acceleration (SA) in the China region allows for a better understanding of regional characteristics and geodynamic origin. Results show that the characteristics of SA differ between the eastern and western hemispheres, with jerks closely related to SA intensity and location. This study provides useful information on the spatiotemporal response relationship between jerks and SA in China since 2000.
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
(2023)
Article
Geosciences, Multidisciplinary
Avto Goguitchaichvili, Esteban Hernandez-Quintero, Rafael Garcia-Ruiz, Vadim Kravchinsky, Ruben Cejudo, Gerardo Cifuentes
Summary: This study compiled data from 32 localities in Mexico to establish a model of geomagnetic field variation. The use of Geomagnetic Repeat Stations provided supplementary data, and methods such as agglomerative hierarchical grouping tree and Chebyshev metrics were utilized to mitigate measurement errors. The Bootstrap method and penalized cubic splines were employed to build the secular variation curve, showing similar trends to global model data.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Alexandre Fournier, Julien Aubert, Vincent Lesur, Erwan Thebault
Summary: Each IGRF model includes a secular variation component describing the evolution of the main magnetic field for the next 5 years, with each Gauss coefficient assumed to undergo independent linear evolution. Physics-based forecasts for candidate SV models have increased, driven by satellite data spanning over two decades and progress in numerical modeling of Earth's core dynamics. Rapid geomagnetic variations identified in satellite data can impact the quality of IGRF predictions, necessitating frameworks that incorporate short-term geomagnetic processes.
EARTH PLANETS AND SPACE
(2021)
Article
Geography, Physical
Venera Dobrica, Cristiana Stefan, Crisan Demetrescu
Summary: This study examined the Earth's surface magnetic field and its secular variation, focusing on the internal constituents and dynamics of the SV foci. By analyzing long time-span geomagnetic models and applying filtering techniques, the study revealed new features of the Earth's surface field evolution, such as the westward drift of the inter-centennial constituent and the westward drift of higher frequency constituents in the equatorial band.
GLOBAL AND PLANETARY CHANGE
(2021)
Article
Geochemistry & Geophysics
Gabriel West, Andreas Nilsson, Alexis Geels, Martin Jakobsson, Matthias Moros, Francesco Muschitiello, Christof Pearce, Ian Snowball, Matt O'Regan
Summary: This study investigates the behavior of the geomagnetic field in polar regions during the late Holocene period. By analyzing well-dated sediment cores from the Chukchi Sea, Arctic Ocean, the authors provide valuable insights into the changes in the geomagnetic field in the Arctic over the past few thousand years.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Geochemistry & Geophysics
Mao Ning, Chen Shi, Yang YongYou, Wu Xu, Li YongBo
Summary: The purpose of this research is to compare the observed secular variations of the geomagnetic field with those calculated by IGRF and WMM, and to evaluate the accuracy of IGRF-12 and WMM2015 in mainland China. Using hourly mean data from 10 geomagnetic reference stations in mainland China from 2009 to 2022, the external interference field and crustal magnetic field were eliminated, and the secular variation of the core field was extracted. The results show that the prediction accuracy of the seven geomagnetic elements in the WMM2015 model is better than that of IGRF-12, but the error increases with time. The maximum 1-year error of the total field intensity of the two models is 13 nT, and the 5-year error reaches 153.65 nT, which does not meet the requirements of high-precision geomagnetic navigation. It is suggested to develop a rapid secular variation model (1 year) by supplementing multi-source magnetic survey data in China to improve prediction accuracy.
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
(2023)
Article
Astronomy & Astrophysics
Alvaro R. Gutierrez Falcon, Bruno S. Zossi, Hagay Amit, Ana G. Elias
Summary: This study analyzes the expected changes in particle trajectories due to the weakening of the Earth's geomagnetic dipole, and highlights the potential consequences for space technologies.
ASTROPHYSICS AND SPACE SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
S. Sharan, B. Langlais, H. Amit, E. Thebault, M. Pinceloup, O. Verhoeven
Summary: Unique information about the dynamo process acting at Jupiter is obtained through modeling and interpreting its magnetic field. By analyzing the fluxgate magnetometer measurements from the Juno mission, a magnetic field model is derived that accurately describes both the main field and the secular variation up to high spherical harmonic degrees. The analysis reveals similarities between Jupiter's magnetic field and Earth's, suggesting dominance of advection and presence of zonal and non-zonal deep fluid motions.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Wellington P. de Oliveira, Gelvam A. Hartmann, Jairo F. Savian, Giovanny Nova, Mauricio Parra, Andrew J. Biggin, Ricardo I. F. Trindade
Summary: Improvements in spatial and temporal coverage of paleomagnetic data are crucial for understanding paleofield behavior over the past 10 million years. This study provides new paleodirectional data from volcanic systems in southwestern Colombia and finds inconsistencies with the expected geocentric axial dipole field direction and geographic north pole.
PHYSICS OF THE EARTH AND PLANETARY INTERIORS
(2022)
Article
Geochemistry & Geophysics
T. Schwaiger, D. Jault, N. Gillet, N. Schaeffer, M. Mandea
Summary: Inference of fluid motion below the core-mantle boundary from geomagnetic observations is a highly non-unique inverse problem. A new method is proposed that provides a unique local estimate of the velocity field by assuming quasi-geostrophic flow and neglecting magnetic diffusion. The method overcomes the underdetermination by inverting the flow at each point of a spherical grid representing the core surface and mitigates the unreliable reconstruction of small-scale flows by smoothing the velocity field using Gaussian process regression.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Multidisciplinary Sciences
Xiao-Jia Zhang, Anton Artemyev, Vassilis Angelopoulos, Ethan Tsai, Colin Wilkins, Satoshi Kasahara, Didier Mourenas, Shoichiro Yokota, Kunihiro Keika, Tomoaki Hori, Yoshizumi Miyoshi, Iku Shinohara, Ayako Matsuoka
Summary: Energetic electron precipitation from Earth's outer radiation belt affects the upper atmosphere and its chemical properties. Low-altitude satellite observations reveal that electron precipitation rates often exceed the conventional upper limit due to nonlinear electron interactions with intense plasma waves, which were not previously considered in radiation belt models.
NATURE COMMUNICATIONS
(2022)
Article
Geochemistry & Geophysics
Steve Lund, Gary Acton, Brad Clement, Makoto Okada, Lloyd Keigwin
Summary: The study presents important information on the paleomagnetic field variations during two specific periods based on PSV and excursion data obtained from ODP sites in the western North Atlantic. By correcting age estimates and comparing records, it reveals significant variability of the geomagnetic field at different timescales and characteristics of excursions, providing insights into the behavior of the magnetic field between reversals.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Review
Environmental Sciences
Christopher C. C. Finlay, Nicolas Gillet, Julien Aubert, Philip W. W. Livermore, Dominique Jault
Summary: The turbulent motions of liquid metal in Earth's outer core generate the geomagnetic field. Observations and simulations have shown that the present-day core motions are dominated by a planetary-scale gyre, a jet in the northern polar region, and waves involving the magnetic field. In this review, we explore the dynamics of these core features and discuss their impact on the Earth's magnetism and rotation.
NATURE REVIEWS EARTH & ENVIRONMENT
(2023)
Article
Geochemistry & Geophysics
Pengshuo Duan, Chengli Huang, Cancan Xu
Summary: The purpose of this study is to determine the appropriate latitude range for the eMAC wave model to accurately describe hydromagnetic waves in the Earth's core. Analytical expressions for the physical properties of eMAC waves are presented, including equatorial confinement, latitudinal distribution, damping rate, and eigen-period. The results show that the eMAC wave model accurately describes core waves for latitudes below 25 degrees and provide insights into the properties of the perturbed magnetic fields caused by eMAC waves.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Astronomy & Astrophysics
Bruno Zossi, Mariano Fagre, Hagay Amit, Ana G. Elias
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2020)
Article
Geosciences, Multidisciplinary
I. Wardinski, D. Saturnino, H. Amit, A. Chambodut, B. Langlais, M. Mandea, E. Thebault
EARTH PLANETS AND SPACE
(2020)
Article
Geochemistry & Geophysics
Filipe Terra-Nova, Hagay Amit
PHYSICS OF THE EARTH AND PLANETARY INTERIORS
(2020)
Article
Geosciences, Multidisciplinary
Rafael Rigaud, Mikhail Kruglyakov, Alexey Kuvshinov, Katia J. Pinheiro, Johannes Petereit, Juergen Matzka, Elena Marshalko
Summary: Vertical magnetic transfer functions estimated at island observatories can constrain the 1-D conductivity distribution of the oceanic lithosphere and upper mantle. The study reveals that depth-dependent oceanic conductivity has a tangible effect on island tippers, while the effects from seasonal variations of oceanic conductivity are found to be too small to be worth consideration.
EARTH PLANETS AND SPACE
(2021)
Article
Engineering, Aerospace
Angel O. U. Parentis, Bruno S. Zossi, Hagay Amit, Ana G. Elias
Summary: The study investigates the effects of the Earth's geomagnetic field on the position and area of polar caps and auroral zones. Results show that as the axial degree increases, the total number of polar caps and auroral zones increases, while their total areas exhibit different patterns under various axial field configurations.
ADVANCES IN SPACE RESEARCH
(2021)
Article
Geosciences, Multidisciplinary
P. Alken, E. Thebault, C. D. Beggan, H. Amit, J. Aubert, J. Baerenzung, T. N. Bondar, W. J. Brown, S. Califf, A. Chambodut, A. Chulliat, G. A. Cox, C. C. Finlay, A. Fournier, N. Gillet, A. Grayver, M. D. Hammer, M. Holschneider, L. Huder, G. Hulot, T. Jager, C. Kloss, M. Korte, W. Kuang, A. Kuvshinov, B. Langlais, J. -M. Leger, V. Lesur, P. W. Livermore, F. J. Lowes, S. Macmillan, W. Magnes, M. Mandea, S. Marsal, J. Matzka, M. C. Metman, T. Minami, A. Morschhauser, J. E. Mound, M. Nair, S. Nakano, N. Olsen, F. J. Pavon-Carrasco, V. G. Petrov, G. Ropp, M. Rother, T. J. Sabaka, S. Sanchez, D. Saturnino, N. R. Schnepf, X. Shen, C. Stolle, A. Tangborn, L. Toffner-Clausen, H. Toh, J. M. Torta, J. Varner, F. Vervelidou, P. Vigneron, I. Wardinski, J. Wicht, A. Woods, Y. Yang, Z. Zeren, B. Zhou
Summary: The IAGA V-MOD working group adopted the thirteenth generation of the IGRF in December 2019, which includes definitive main field models for epoch 2015.0 and 2020.0, as well as predictive linear secular variations for 2020.0 to 2025.0. This update provides equations, spherical harmonic coefficients, and maps for magnetic parameters and their predicted changes from 2020.0 to 2025.0.
EARTH PLANETS AND SPACE
(2021)
Article
Geosciences, Multidisciplinary
Hagay Amit, Filipe Terra-Nova, Maxime Lezin, Ricardo I. Trindade
Summary: The South Atlantic Anomaly (SAA) is a region on Earth's surface with a particularly low intensity of the magnetic field. Accurate characterization of the SAA is crucial for understanding core dynamics, geodynamo, and addressing societal issues. Research indicates that the SAA area and center exhibit time dependency, including periods of stability, eastward drift, and rapid southward drift.
EARTH PLANETS AND SPACE
(2021)
Article
Geochemistry & Geophysics
Wellington P. Oliveira, Gelvam A. Hartmann, Filipe Terra-Nova, Daniele Brandt, Andrew J. Biggin, Yael A. Engbers, Richard K. Bono, Jairo F. Savian, Daniel R. Franco, Ricardo I. F. Trindade, Thiago R. Moncinhatto
Summary: The study investigates the latitudinal structure of paleosecular variation (PSV) and the time-averaged field (TAF) for the Brunhes normal and Matuyama reverse chrons over the past 10 million years. Statistical analysis reveals a low latitudinal dependence of PSV and an apparent hemispheric PSV asymmetry, with a stronger latitudinal signature in the southern hemisphere.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geochemistry & Geophysics
I Wardinski, H. Amit, B. Langlais, E. Thebault
Summary: By utilizing MESSENGER probe data, the study infers the internal structure of Mercury's core and suggests that the inner core size ranges from 500 to 660 km, with a corresponding stratified layer thickness of 880 to 500 km. The research provides new insights into the core structure of a planet based on magnetic field observations.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2021)
Article
Multidisciplinary Sciences
Plinio Jaqueto, Ricardo I. F. Trindade, Filipe Terra-Nova, Joshua M. Feinberg, Valdir F. Novello, Nicolas M. Strikis, Peter Schroedl, Vitor Azevedo, Beck E. Strauss, Francisco W. Cruz, Hai Cheng, R. Lawrence Edwards
Summary: Speleothems can provide continuous and high-quality records of the geomagnetic field. The paleomagnetic records of a mid-to-late Holocene stalagmite from Brazil show small angular variations and relatively steady paleointensity, contrasting with the fast variations observed in younger speleothems from the same region.
NATURE COMMUNICATIONS
(2022)
Article
Astronomy & Astrophysics
Gabriel Soares, Yosuke Yamazaki, Achim Morschhauser, Jurgen Matzka, Katia J. Pinheiro, Claudia Stolle, Patrick Alken, Akimasa Yoshikawa, Kornyanat Hozumi, Atul Kulkarni, Pornchai Supnithi
Summary: This study proposes a new technique for modeling the equatorial electrojet (EEJ) based on principal component analysis (PCA) and compares its performance with existing models. By using ground-satellite geomagnetic data, the researchers successfully determine the amplitudes of solar tides and find a remarkable correlation between tidal signatures in the EEJ and tidal signatures derived from neutral atmosphere temperature observations. The results of the study suggest that meaningful EEJ spectra related to solar tides can be obtained even with relatively short observation periods.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Filipe Terra-Nova, Hagay Amit, Gael Choblet, Gabriel Tobie, Mathieu Bouffard, Ondrej Cadek
Summary: This study investigates the effects of a heterogeneous seafloor heat flux pattern on convection and heat transfer in the subsurface ocean of large icy worlds. The research finds correlations between intense inner boundary heat flux and intense outer boundary heat flux, and suggests the existence of polar cooling for Titan's sub-surface ocean.
Article
Geochemistry & Geophysics
Maxime Lezin, Hagay Amit, Filipe Terra-Nova, Ingo Wardinski
Summary: The geomagnetic field exhibits weak or reversed field in the polar regions and intense flux patches at the edges of the intersection of the inner-core tangent cylinder (TC) with the core-mantle boundary (CMB). This high-latitude field morphology is consistent with the thermal wind theory inside the TC, which suggests that polar upwellings disperse magnetic field lines. The presence of a westward jet at high latitudes in the northern hemisphere and the absence of such a jet in the southern hemisphere also align with the TC dynamical theory.
PHYSICS OF THE EARTH AND PLANETARY INTERIORS
(2023)
Article
Geosciences, Multidisciplinary
Bruno Zossi, Hagay Amit, Mariano Fagre, Ana G. Elias
Summary: This study analyzes the long-term changes in core origin of the auroral zone area utilizing data from the Auroral Boundary Index (ABI) database. By applying a four-step filtering process, the effects of solar activity on the auroral boundary temporal variation are minimized, resulting in consistent observations of area increase/decrease in the northern and southern hemispheres. The comparison between observational evidence and model predictions provides valuable insights into the recent surprising decrease of the auroral zone area.
