Interpretation of Core Field Models

Kuang, Weijia; Tangborn, Andrew

doi:10.1007/978-90-481-9858-0_12

Cited by 5 publications

(4 citation statements)

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“…Geomagnetic jerks are defined as as V-like or Λ-like changes in the SV and occur in a time period of a few months (Courtillot and LeMouёl, 1984;Morozova et al, 2014;Kang et al, 2020). "The geomagnetic jerks are due to interactions of the core field and the rapid timevarying core flow" (Kuang et al, 2011). Since Malin and Hodder (1982), Courtillot and Le MouёL (1984) discovered the geomagnetic jerk in 1969, ten jerks have been detected in observatories from 1933 to , of which 1969, 1978(Alexandrescu et al,1996), 1991( De Michelis et al, 1998), 1999(Mandea et a.l, 2000), 2003(Olsen et al, 2007Feng et al, https://doi.org/10.5194/essd-2022-203…”

Section: Figure 6 the Ahmvs Record Of January 1955 At Sshmentioning

confidence: 99%

Rescue and quality control of historical geomagnetic measurement at SheShan Observatory, China

Zhang

Fu²,

Wang³

et al. 2022

Preprint

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Abstract. The Sheshan geomagnetic observatory (IAGA code SSH), China was built in Xujiahui, Shanghai in 1874 and moved to Sheshan, Shanghai at the end of 1932. So far, SSH has a history of nearly 150 years. It is one of the earliest geomagnetic observatory in China and one of the geomagnetic stations with the longest history in the world.In this paper, we present the rescue and quality control of the historical data at Sheshan observatory (SSH) from 1933 to 2019. The rescued data are the absolute hourly mean values of D, H and Z components. Some of these data are paper-based records, and some are stored in a floppy disk in BAS, DBF, ACCESS and other file formats. After digitization and format transformation, we imported the data into the Toad database to achieve the unified data management. We performed statistics of continuity rate, visual analysis, outliers detects and data correction on the stored data. Then we conducted the consistency test of daily variation and secular variation by comparing the corrected data with these of the reference observatory data, and the computational data of the COV-OBS model, respectively. The consistency test revealed fairly good agreement. However, the individual data should be used with caution, because these data are suspicious values, but there is not any explanation or change registered in the available metadata and logbooks. Finally we present an example of the datasets in discriminating geomagnetic jerks. The digitized and quality-controlled AHMVs data are available at: https://doi.org/10.5281/zenodo.6584285 (Zhang et al, 2022).

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Section: Figure 6 the Ahmvs Record Of January 1955 At Sshmentioning

confidence: 99%

Rescue and quality control of historical geomagnetic measurement at SheShan Observatory, China

Zhang

Fu²,

Wang³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…where X denotes the geomagnetic field components D, H , and Z. Geomagnetic jerks are defined as V-like or -like changes in the SV and occur in a time period of a few months (Courtillot and Le Mouël, 1984;Morozova et al, 2014;Kang et al, 2020). "The geomagnetic jerks are due to interactions of the core field and the rapid time-varying core flow" (Kuang and Tangborn, 2011). Since Malin and Hodder (1982), Courtillot and Le Mouël (1984) discovered the geomagnetic jerk in 1969, 10 jerks have been detected in observatories from 1933 to 2020, of which 1969, 1978(Alexandrescu et al, 1996), 1991(De Michelis et al, 1998), 1999(Mandea et al, 2000Zhang et al, 2008a), 2003(Mandea and Olsen, 2007Feng et al, 2018;He et al, 2019(Kotzé, 2010, and 2014 (Brown et al, 2016;Kloss and Finlay, 2019;Finlay et al, 2016;Kang et al, 2020) were global events.…”

Section: Application Examples Of Ssh Datasetsmentioning

confidence: 99%

Rescue and quality control of historical geomagnetic measurement at Sheshan observatory, China

Zhang

Wang

et al. 2022

Earth Syst. Sci. Data

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Abstract. The Sheshan Geomagnetic Observatory (International Association of Geomagnetism and Aeronomy (IAGA) code SSH), China was built in Xujiahui, Shanghai in 1874 and moved to Sheshan, Shanghai at the end of 1932. So far, the SSH has a history of nearly 150 years. It is one of the earliest geomagnetic observatories in China and one of the geomagnetic observatories with the longest history in the world. In this paper, we present the rescue and quality control (QC) of the historical data at the SSH from 1933 to 2019. The rescued data are the absolute hourly mean values (AHMVs) of declination (D), horizontal (H), and vertical (Z) components. Some of these data are paper-based records and some are stored in a floppy disk in BAS, DBF, MDB, and other file storage formats. After digitization and format transformation, we imported the data into the Toad database to achieve the unified data management. We performed statistics of completeness, visual analysis, outliers detects, and data correction on the stored data. We then conducted the consistency test of daily variation and secular variation (SV) by comparing the corrected data with the data of the reference observatory, and the computational data of the COV-OBS model, respectively. The consistency test reveals good agreement. However, the individual data should be used with caution because these data are suspicious values, but there is not any explanation or change registered in the available metadata and logbooks. Finally, we present examples of the datasets in discriminating geomagnetic jerks and study of storms. The digitized and quality-controlled AHMVs data are available at: https://doi.org/10.5281/zenodo.7005471 (Zhang et al., 2022).

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“…Although they operate in different regimes and it is not (yet) possible to set all fundamental control parameters to the values assumed for Earth, they show more and more characteristics similar to features found in data‐based models and bring us closer to fully understanding the mechanisms generating the geomagnetic field. The past decade has seen increasing efforts to combine observations and theory in data assimilation approaches to predict the future geomagnetic core field evolution, using methodologies such as developed in meteorology for weather forecasting (see, e.g., Fournier et al, ; Hulot et al, ; Kuang & Tangborn, ). It is even becoming possible to simulate some of the core dynamics in large experiments that use liquid sodium as the electrically conducting material to generate magnetic fields (see, e.g., Cardin & Olson, ).…”

Section: Geomagnetism Today: a Short Tourmentioning

confidence: 99%

Geomagnetism: From Alexander von Humboldt to Current Challenges

Korte

Mandea

2019

Geochem Geophys Geosyst

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The Earth's magnetic field shields our habitat against potentially harmful charged particles from outer space. Moreover, it is an important source of information about Earth's deep interior and geological history, both inaccessible to direct observations. Geomagnetism, the study of all aspects of the Earth's magneticfield, formed as a field of natural sciences in the early nineteenth century, largely under the influence of two prominent polymaths, Alexander von Humboldt and Carl Friedrich Gauss. On the occasion of the AGU 2019 centennial and Alexander von Humboldt's 250th anniversary, we link Humboldt's activities in geomagnetism with modern research in this domain and its challenges. Based on magnetic field observations during his scientific journeys, Alexander von Humboldt determined the increase of magnetic intensity with distance from the equator. He initiated coordinated observations across the globe and thus laid the foundation for international data exchange and collaboration. Observation is a prerequisite to a better understanding of the Earth's magnetic field with its various sources from the Earth's core, lithosphere, and electrical current systems outside the Earth, with a multitude of applications from navigation, exploration, natural hazard assessment, and study of Earth's evolution. A full understanding of the physical processes underlying the various geomagnetic field sources is mandatory to tackle the challenge of forecasting the future geomagnetic field evolution and to take advantage of the information that the geomagnetic field can provide about the Earth's history, geological and tectonic conditions and processes, and the near‐Earth's space environment.

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Interpretation of Core Field Models

Cited by 5 publications

References 64 publications

Rescue and quality control of historical geomagnetic measurement at SheShan Observatory, China

Rescue and quality control of historical geomagnetic measurement at SheShan Observatory, China

Rescue and quality control of historical geomagnetic measurement at Sheshan observatory, China

Geomagnetism: From Alexander von Humboldt to Current Challenges

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