The inclusion of the vector components from the satellite missions (Magsat, Ørsted, CHAMP, SAC-C) has provided the most accurate global models, such as the comprehensive geomagnetic field models ( Sabaka et al., 2015 and reference therein, among others).
Anomaly 2 mission 7 series#
The era of the satellites measuring started with the earlier POGO series when the first satellite, the OGO-2, was launched in October 1965 to measure the total intensity of the geomagnetic field. Only from the middle of the twentieth century the geomagnetic ground data have been complemented by satellite data at different altitudes above the Earth's surface. At the end of the nineteenth century, the permanent geomagnetic observatories were established providing the continuous time-series of geomagnetic data. The use of these historical data has allowed having a picture of the geomagnetic field behavior for the last four centuries as reflected by the first historical model published by Jackson et al. This is the case of the directional data (i.e., inclination and declination), but not intensity data because Carl-Friedrich Gauss performed the first absolute intensity measurements in 1832 ( Gauss, 1833). The historical geomagnetic data ( Jonkers et al., 2003) are available only since the sixteenth century.
The dynamics of the Earth's core is a nowadays challenge for the geophysics community and detailed knowledge of the secular variation (SV) of the Earth's Magnetic field can shed light on this issue.
Anomaly 2 mission 7 Patch#
In addition, we demonstrate that the quadrupole field mainly controls this reversal patch along with the rapid decay of the dipolar field.
Our results reveal that one of the reversed polarity patch located at the CMB under the South Atlantic Ocean is growing with a pronounced rate of −2.54♱0 5 nT per century and with western drift. In this paper we carry out a detailed study about this issue using the most recent models that also include data from the last ESA mission Swarm. Several studies associate this anomaly as an indicator of an upcoming geomagnetic transition, such an excursion or reversal. Its extent area at the Earth's surface is continuously growing since the intensity instrumental measurements are available covering part of the Southern Hemisphere and centered in South America.
The South Atlantic Anomaly is nowadays one of the most important features of the Earth's magnetic field. 2Dipartimento di Ingegneria e Geologia (INGEO), Università G.1Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy.
Javier Pavón-Carrasco 1 * † and Angelo De Santis 1,2
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