Geomagnetic fields
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Leeds dynamo simulations for the analysis of rapid changes in the geomagnetic field. In each folder, the following file can be found: - state.cdf.in - the configuration file used as an intial condition to launch each simulation Some folders have multiple state.cdf.in files for each run of the same simulation, if only part of the data was needed to be reproduced. Additionally, most folders contain: - LSD.info/main.info - Contains details of the parameters for each simulation, which can be used for reference when recompiling the code - LSD.out/main.out - the exectuable used to submit a simulation to a hpc; for the code to be reran, this would have to be recompiled (see Leeds_Dynamo_Code_Manual.pdf) - run.bolt/run.sh - the scripts used to submit a simulation to the leeds hpc (.sh file) or archer2 (.bolt file) Details of how to run the Leeds dynamo code can be found in Leeds_Dynamo_Code_Manual.pdf, which contains a more in-depth description of input parameters, boundary conditions, output data etc. The parameters for each simulation can also be found in the spreadsheet 'SimulationsLog'. More details about the difference between thermally-driven and thermochemically-driven cases can be found in Nakagawa and Davies, 2022. Note all simulations have Prandtl number Pr=1. We have ran a series of simulations to help us elucidate the origin of rapid changes in the Earth's magnetic field. Observational models of the magnetic field have found changes in field intensity and direction that significantly faster than the values and averages for the modern field. The simulations provided here have been analysed to find the features that best reproduce dynamical and morphological agreement with the observed field, as well as to find rapid changes in the simulated field that are in agreement with that of the observed field (see Nakagawa and Davies 2022). Simulations have been ran using the Leeds Dynamo Code, and the configuration files provided here allow users to reproduce and interpret the data used for analysis.
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All the raw experimental data obtained for the study reported in Hodgson, E., Grappone, J. M., Biggin, A. J., Hill, M. J., & Dekkers, M. J. (2018). Thermoremanent behavior in synthetic samples containing natural oxyexsolved titanomagnetite. Geochemistry, Geophysics, Geosystems, 19. https://doi.org/10.1029/2017GC007354
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This dataset contains extremal forecast of latitutude (lat), longitude (lon) and intensity of the geomagnetic dipole between 2019 and 2119. The geomagnetic dipole is evolved by a fluid flow at the core-mantle boundary that maximises the rate-of-change of the dipole latitude. The forecast is calculated from the year 2019 assuming that the geomagnetic field is described by the CHAOS-7 dataset. The optimisation procedure is described in https://doi.org/10.3390/geosciences11080318
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This dataset comprises palaeointensity measurements from the Bourinot volcanic units (~505 Ma) and the Itabaiana dyke swarm (~525 Ma), with associated palaeomagnetic and rock magnetic metadata. The dataset covers Cambrian igneous units from two geographically distinct regions: the Bourinot volcanic sequence of Cape Breton Island, Nova Scotia (Avalonia), dated to ~505 Ma, and the Itabaiana dyke swarm of northeastern Brazil (Gondwana), dated to ~525 Ma. Together, these units sample magmatic rocks emplaced on separate palaeocontinental blocks during the early–middle Cambrian, providing geographically and tectonically independent constraints on geomagnetic field behaviour during this interval. The Excel file contains specimen-level palaeomagnetic and palaeointensity measurement data from Cambrian igneous units. It includes stepwise laboratory measurement records for individual specimens, comprising directional data (declination and inclination), magnetic moment and vector components, and associated experimental metadata. Each row represents a single laboratory measurement step within demagnetisation or palaeointensity experiments (e.g. IZZI-type Thellier protocols). The columns document specimen identifiers, experiment and method codes, instrument information, analysts, treatment conditions (thermal, alternating-field, and microwave where applicable), applied laboratory fields, measurement sequence, quality flags, and timestamps. Supporting metadata include citations, laboratory standards, and descriptive fields required for reproducibility and data reuse. The dataset is formatted to be compatible with established palaeomagnetic data standards and supports reconstruction of full experimental workflows for palaeointensity analysis.
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A new family of spherical harmonic geomagnetic field models spanning the past 9000 yr based on magnetic field directions and intensity stored in archaeological artefacts, igneous rocks and sediment records. The pfm9k geomagnetic field models and datafiles as well as the individual bootstraps of the pfm9k.1b geomagnetic field model presented in A. Nilsson, R. Holme, M. Korte, N. Suttie and M. Hill (2014): Reconstructing Holocene geomagnetic field variation: new methods, models and implications. Geophys. J. Int., doi: 10.1093/gji/ggu120 are included here.
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Data used to create the model outputs for NERC Grant NE/J004693/1, Geophysical Modelling of Geomagnetically Induced Currents in the UK. Data and code required to recreate results in the following papers: Beggan, C. (2015), Sensitivity of Geomagnetically Induced Currents to Varying Auroral Electrojet and Conductivity models, Earth Planets and Space, 67 (1), doi:10.1186/s40623-014-0168-9. http://nora.nerc.ac.uk/509877/ Beggan, C., Beamish, D., Kelly, G.S., Richards, A., and A. W. P. Thomson (2013), Prediction of Geomagnetically Induced Currents in the United Kingdom's National Grid, Space Weather, 11, doi: 10.1002/swe.20065. http://nora.nerc.ac.uk/502627/ Pulkkinen, A., Bernabeu, E., Eichner, J., Beggan C., and A. Thomson (2012), Generation of 100-year geomagnetically induced current scenarios, Space Weather, Vol. 10, No. 4, S04003, doi:10.1029/2011SW000750 Geological areas - United Kingdom, Ireland, North Sea