High-resolution paleomagnetic secular variation and relative paleointensity records from the western Canadian Arctic: implication for Holocene stratigraphy and geomagnetic field behaviourThis article is one of a series of papers published in this Special Issue on the theme Polar Climate Stability Network.GEOTOP Contribution 2008-0024.

2008 ◽  
Vol 45 (11) ◽  
pp. 1265-1281 ◽  
Author(s):  
Francesco Barletta ◽  
Guillaume St-Onge ◽  
James E.T. Channell ◽  
André Rochon ◽  
Leonid Polyak ◽  
...  
Keyword(s):  
Dipole Moment ◽  
High Resolution ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Special Issue ◽  
Polar Climate ◽  
Climate Stability ◽  
Relative Paleointensity ◽  
Holocene Stratigraphy ◽  
Field Behaviour

Two piston cores recovered from the Chukchi and the Beaufort seas document Arctic Holocene geomagnetic field behaviour and highlight the potential of secular variation and relative paleointensity as a regional chronostratigraphic tool. Several centennial- to millennial-scale Holocene declination and inclination features can be correlated in both cores, with other high-resolution western North American lacustrine and volcanic paleomagnetic records and with records of changes in Earth’s dipole moment, supporting the geomagnetic origin of these features and implying that they are associated with changes in Earth’s dipole moment.

A comparison of geomagnetic secular variation as recorded by historical, archaeomagnetic and palaeomagnetic measurements

1982 ◽  
Vol 306 (1492) ◽  
pp. 103-112 ◽  
Keyword(s):  
Magnetic Field ◽  
Lake Sediments ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Secular Change ◽  
Mathematical Approach ◽  
Geomagnetic Secular Variation ◽  
The Past ◽  
Palaeomagnetic Data ◽  
Field Behaviour

Palaeomagnetic methods can extend the documentary record of changes in the Earth’s magnetic field far into the past. Tolerable agreement is found between various methods, demonstrating the geophysical value of palaeomagnetic experiments. Combining results from the different approaches of investigating secular change can lead to a better perspective and to superior models of geomagnetic field behaviour. Lake sediments have recently been found to hold remarkably detailed signatures of past field changes. A mathematical approach to formulating an empirical description of global geomagnetic field behaviour is proposed and applied to palaeomagnetic data spanning the last 10 ka.

scholarly journals High-resolution evidence for dynamic transitional geomagnetic field behaviour from a Miocene reversal, McMurdo Sound, Ross Sea, Antarctica

2007 ◽  
Vol 59 (7) ◽  
pp. 815-824 ◽  
Author(s):  
Andrew P. Roberts ◽  
Anisch Bakrania ◽  
Fabio Florindo ◽  
Christopher J. Rowan ◽  
Christopher R. Fielding ◽  
...  
Keyword(s):  
High Resolution ◽  
Geomagnetic Field ◽  
Ross Sea ◽  
Mcmurdo Sound ◽  
Field Behaviour

Measuring Exposome Associated with Health

2020 ◽  
pp. 46-50
Keyword(s):  
Mass Spectrometry ◽  
Remote Sensing ◽  
High Resolution ◽  
Biological Effect ◽  
High Resolution Mass Spectrometry ◽  
The Body ◽  
Ecological Environment ◽  
Special Issue ◽  
The Life Course ◽  
Resolution Mass

The concept of exposome has received increasing discussion, including the recent Special Issue of Science –"Chemistry for Tomorrow's Earth,” about the feasibility of using high-resolution mass spectrometry to measure exposome in the body, and tracking the chemicals in the environment and assess their biological effect. We discuss the challenges of measuring and interpreting the exposome and suggest the survey on the life course history, built and ecological environment to characterize the sample of study, and in combination with remote sensing. They should be part of exposomics and provide insights into the study of exposome and health.

scholarly journals Predictions of the geomagnetic secular variation based on the ensemble sequential assimilation of geomagnetic field models by dynamo simulations

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Sabrina Sanchez ◽  
Johannes Wicht ◽  
Julien Bärenzung
Keyword(s):  
Magnetic Field ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Wave Number ◽  
Main Magnetic Field ◽  
Candidate Model ◽  
Uncertainty Estimates ◽  
Geomagnetic Field Models ◽  
Dipole Configuration

Abstract The IGRF offers an important incentive for testing algorithms predicting the Earth’s magnetic field changes, known as secular variation (SV), in a 5-year range. Here, we present a SV candidate model for the 13th IGRF that stems from a sequential ensemble data assimilation approach (EnKF). The ensemble consists of a number of parallel-running 3D-dynamo simulations. The assimilated data are geomagnetic field snapshots covering the years 1840 to 2000 from the COV-OBS.x1 model and for 2001 to 2020 from the Kalmag model. A spectral covariance localization method, considering the couplings between spherical harmonics of the same equatorial symmetry and same azimuthal wave number, allows decreasing the ensemble size to about a 100 while maintaining the stability of the assimilation. The quality of 5-year predictions is tested for the past two decades. These tests show that the assimilation scheme is able to reconstruct the overall SV evolution. They also suggest that a better 5-year forecast is obtained keeping the SV constant compared to the dynamically evolving SV. However, the quality of the dynamical forecast steadily improves over the full assimilation window (180 years). We therefore propose the instantaneous SV estimate for 2020 from our assimilation as a candidate model for the IGRF-13. The ensemble approach provides uncertainty estimates, which closely match the residual differences with respect to the IGRF-13. Longer term predictions for the evolution of the main magnetic field features over a 50-year range are also presented. We observe the further decrease of the axial dipole at a mean rate of 8 nT/year as well as a deepening and broadening of the South Atlantic Anomaly. The magnetic dip poles are seen to approach an eccentric dipole configuration.

scholarly journals Geomagnetic Virtual Observatories: monitoring geomagnetic secular variation with the Swarm satellites

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Magnus D. Hammer ◽  
Grace A. Cox ◽  
William J. Brown ◽  
Ciarán D. Beggan ◽  
Christopher C. Finlay
Keyword(s):  
Time Series ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Time Windows ◽  
Low Earth Orbit ◽  
Data Selection ◽  
Spherical Harmonic Analysis ◽  
Core Field ◽  
The Core ◽  
Swarm Satellites

AbstractWe present geomagnetic main field and secular variation time series, at 300 equal-area distributed locations and at 490 km altitude, derived from magnetic field measurements collected by the three Swarm satellites. These Geomagnetic Virtual Observatory (GVO) series provide a convenient means to globally monitor and analyze long-term variations of the geomagnetic field from low-Earth orbit. The series are obtained by robust fits of local Cartesian potential field models to along-track and East–West sums and differences of Swarm satellite data collected within a radius of 700 km of the GVO locations during either 1-monthly or 4-monthly time windows. We describe two GVO data products: (1) ‘Observed Field’ GVO time series, where all observed sources contribute to the estimated values, without any data selection or correction, and (2) ‘Core Field’ GVO time series, where additional data selection is carried out, then de-noising schemes and epoch-by-epoch spherical harmonic analysis are applied to reduce contamination by magnetospheric and ionospheric signals. Secular variation series are provided as annual differences of the Core Field GVOs. We present examples of the resulting Swarm GVO series, assessing their quality through comparisons with ground observatories and geomagnetic field models. In benchmark comparisons with six high-quality mid-to-low latitude ground observatories we find the secular variation of the Core Field GVO field intensities, calculated using annual differences, agrees to an rms of 1.8 nT/yr and 1.2 nT/yr for the 1-monthly and 4-monthly versions, respectively. Regular sampling in space and time, and the availability of data error estimates, makes the GVO series well suited for users wishing to perform data assimilation studies of core dynamics, or to study long-period magnetospheric and ionospheric signals and their induced counterparts. The Swarm GVO time series will be regularly updated, approximately every four months, allowing ready access to the latest secular variation data from the Swarm satellites.

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