State of the geomagnetic field

Chulliat, Arnaud ORCID: https://orcid.org/0000-0001-7414-9631; Brown, William ORCID: https://orcid.org/0000-0001-9045-9787; Alken, Patrick ORCID: https://orcid.org/0000-0001-8983-3153; Macmillan, Susan ORCID: https://orcid.org/0000-0001-6213-2672; Nair, Manoj ORCID: https://orcid.org/0000-0002-0541-0127; Meyer, Brian ORCID: https://orcid.org/0000-0002-9307-9736. 2022 State of the geomagnetic field. NOAA-NCEI.

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Abstract/Summary

The performance of the World Magnetic Model 2020 (WMM2020) was assessed by comparing its predictions on January 1, 2023 with that of a more recent model inferred from data collected by the European Space Agency (ESA) Swarm satellites from November 2013 until September 2022. For all magnetic field components, the WMM2020 global root-mean-square error increased by less than 5% over the past three years and remained well below the maximum error allowed by the U.S. Department of Defense WMM specification. In addition, the WMM2020 secular variation was again deemed an accurate approximation of the actual secular variation observed at ground-based observatories and Swarm-based geomagnetic virtual observatories in 2021 and 2022. This suggests that nonlinear changes in the Earth’s magnetic field have remained small over the past three years. Since 2020, the north magnetic dip pole has moved at an average speed of 43 km/yr, and the south magnetic dip pole at 9 km/yr. Neither underwent any noticeable change in direction. These movements led to minor changes in the shape and location of the WMM blackout zones, where compass accuracy is reduced. The South Atlantic Anomaly, where the geomagnetic field intensity is smallest, continued to deepen (by about 80 nT at sea level) and move westwards (its center moved by about 70 km at sea level). Over the past year, three strong to severe geomagnetic storms occurred; these storms led to significant but temporary effects on WMM performance, mostly at high geomagnetic latitudes.

Item Type:	Publication - Report (Technical Report)
Digital Object Identifier (DOI):	https://doi.org/10.25923/8r5d-fj70
Funders/Sponsors:	National Centers for Environmental Information, NOAA, British Geological Survey, National Geospatial Intelligence Agency, Cooperative Institute for Research in Environmental Sciences, NATO, Defence Geographic Centre
Additional Keywords:	Geomagnetism, World Magnetic Model
NORA Subject Terms:	Earth Sciences
Date made live:	16 Jun 2023 10:37 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/533730

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