Cullen’s Rule of Thumb states that an individual will either laugh or cry whenever they scratch away at the tarnished “science” of an “Earth Science”.
However, Geomagnetism is really different because it makes me [both] laugh and cry.
In this respect the “science” of Geomagnetism is truly exception, even more exception than the “science” of Catastrophic Anthropomorphic Global Warming [CAGW].
The Geomagnetic cult has grown and prospered by nurturing the fabulous fables of Team Tweedledee [Palaeomagnetism] and Team Tweedledum [Plate Tectonics].
Paleomagnetists led the revival of the continental drift hypothesis and its transformation into plate tectonics.
Apparent polar wander paths provided the first clear geophysical evidence for continental drift, while marine magnetic anomalies did the same for seafloor spreading.
Paleomagnetism continues to extend the history of plate tectonics back in time and are applied to the movement of continental fragments, or terranes.
Reviewing the mainstream Magnetic North Pole location data [published by the “usual suspects”] reveals wonderful “hockey sticks” that can be rolled out [in a “Plan B” scare scenario] when the Global Warming scam finally hits the buffers.
Unsurprisingly, the “data” is spliced together from two different sources.
Unsurprisingly, the “data” is entirely based upon “models”.
Unsurprisingly, the “hockey stick” really “takes off” in the satellite age of post normal science.
From 1,590 to 1980 the “data” is derived from the GUFM model which is largely based upon “ship log data” [and appears to bear all the same hallmarks that are stamped upon the “bucket” and “engine intake” sea surface temperature dataset].
From 1981 the “data” is derived from the IGRF model which has amazingly predicted the position of the Magnetic North Pole through to 2015. No doubt these model predictions are even more robust [and even more reliable] that the CAGW temperature predictions.
NOAA notes that the path “reflects the chaotic and independent movement of magnetic poles” whilst a more cynical reviewer might muse that it simply reflects the chaotic and independent movement of computer models.
NOAA also notes that magnetic poles “derived in this fashion are more closer to the experimentaly observed poles” whilst a more cynical reviewer might wonder whether the “experimentally observed poles” might actually be nearer the truth.
Movement of magnetic poles from 1590 to 2010
The magnetic poles or dip pole are computed from all the Gauss coefficients using an iterative method. Magnetic poles derived in this fashion are more closer to the experimentaly observed poles.
Based on the current WMM model, the 2010 location of the north magnetic pole is 84.97°N and 132.35°W and the south magnetic pole is 64.42°S and 137.34°E.
The Google map below illustrates the movement of the magnetic poles during 1590 to 2010 derived from the GUFM (1590 – 1980) and IGRF (1981 – 2010) models.
The GUFM model (Jackson et al., 2000, Four centuries of geomagnetic secular variation from historical records, Phil. Trans. Roy. Soc. Lond. A, 358, 957- 90.) covers the period 1590 -1990 and is based on ship log data.
The path reflects the chaotic and independent movement of magnetic poles.
For example, the present rate of progression of the north magnetic pole (55 km/year) is significantly higher than that of the South Pole.
There is a reason why NOAA gets logically [and linguistically] confused when it discusses the locations of the Magnetic poles.
The embarrassingly simple reason is that the locations of these Magnetic Poles that NOAA are referring to are purely manmade [calculated] artefacts that don’t really exist in the real world.
However, to truly comprehend the virtual reality world of Magnetic Poles [and Geomagnetism] it is necessary to understand a fundamental tenet of their belief system: the Geomagnetic Dipole.
Earth’s magnetic field (also known as the geomagnetic field) is the magnetic field that extends from the Earth’s inner core to where it meets the solar wind, a stream of energetic particles emanating from the Sun.
Its magnitude at the Earth’s surface ranges from 25 to 65 µT (0.25 to 0.65 G).
It is approximately the field of a magnetic dipole tilted at an angle of 11 degrees with respect to the rotational axis—as if there were a bar magnet placed at that angle at the center of the Earth.
The concept of the “Geomagnetic Dipole” [as if a bar magnet was placed at the centre of the Earth] is fundamental to the Geomagnetic faith system.
Believing in the “Geomagnetic Dipole” means there can be only one true “Magnetic North Pole” and there can only be one true “Magnetic South Pole”.
This is the sacred trinity of Geomagnetism.
Unfortunately, there is a problem.
In fact, there are two very large problems.
Firstly, the Earth has two Magnetic North Poles.
Secondly, the Earth has two Magnetic South Poles.
This also means there is no Geomagnetic Dipole.
This is very sad for the followers of Geomagnetism.
However, as with all good post normal science, the followers of Geomagnetism don’t let “data” or “facts” undermine a good [money spinning] franchise – especially when there is good money to made writing geo-dynamo theories and playing with geo-dynamo computer models.
Computer simulation of the Earth’s field in a normal period between reversals.
The lines represent magnetic field lines, blue when the field points towards the center and yellow when away. The rotation axis of the Earth is centered and vertical.
The dense clusters of lines are within the Earth’s core.
There is also good money to be made modelling the notional position of the “one and only true” North [and South] Magnetic Pole [for the faithful “scientists” who follow Geomagnetism] based upon some sort of “average position” between the two real magnetic poles in the north [and south].
[This is the notional Magnetic Pole position data from NOAA that was graphed earlier in this post.]
Furthermore, there is bonus buckshee to be made calculating the hypothetical location of the magnetic north and south poles based upon a hypothetical geomagnetic dipole.
The Geomagnetic poles (dipole poles) are the intersections of the Earth’s surface and the axis of a bar magnet hypothetically placed at the center the Earth by which we approximate the geomagnetic field. There is such a pole in each hemisphere, and the poles are called as “the geomagnetic north pole” and “the geomagnetic south pole”, respectively.
On the other hand, the magnetic poles are the points at which magnetic needles become vertical.
There also are “the magnetic north pole” and “the magnetic south pole”.
The geomagnetic or magnetic south (north) poles correspond to the N (S) -pole of a magnet.
However, once Geomagnetism has established the hypothetical magnetic poles for the hypothetical geomagnetic dipole then they can hit the jackpot by calculating hypothetical geomagnetic anomalies.
EMAG2 is a significant update over our first global magnetic anomaly grid, EMAG3, which provided the base grid for the World Digital Magnetic Anomaly Map of the Commission of the World Geological Map.
As reflected in the name the resolution has been improved from 3 arc minute to 2 arc minute and the altitude has been reduced from 5 km to 4 km above geoid.
Additional grid and trackline data have been included, both over land and the oceans.
Interpolation between sparse tracklines in the oceans was improved by directional gridding and extrapolation, based on an oceanic crustal age model .
The longest wavelengths (larger than 330 km) were replaced with the latest CHAMP lithospheric field model MF6.
EMAG2 is specified as a global 2-arc-minute resolution grid of the anomaly of the magnetic intensity at an altitude of 4 km above mean sea level.
It was compiled from satellite, marine, aeromagnetic and ground magnetic surveys (see our acknowledgment of data providers and collaborators).
Unsurprisingly, the Earth’s real magnetic field is totally anomalous when compared to the hypothetical geomagnetic geo-dynamo dipole.
This is simply because the Earth is not a dipole.
However, for the surreal “science” of Geomagnetism, these hypothetical anomalies are a treasure trove that just keeps on giving and giving and giving!