The South Atlantic Anomaly

by Mori
November 7, 2007
from Forgetomori Website

The map above does not represent the most common destination for fleeing Hollywood villains.


It’s in fact the South Atlantic Anomaly, a region where the Earth’s inner van Allen radiation belt makes its closest approach to the planet’s surface. The result is that, for a given altitude, the radiation intensity is higher over this region than elsewhere.


Brazilians are blessed indeed.


The Anomaly in the radiation belt results from the fact that the planet’s magnetic field is not perfectly aligned with its geographic center and poles.


Which means the magnetic field is slightly stronger in the North, and moves around the geographic poles, leaving the area around Brazil and the South Atlantic closer to the radiation belts.

Fortunately, the effects of it over humans on the surface of the planet are not significant. Unfortunately, it’s very relevant to orbiting satellites - the Hubble Space telescope does not take observations while passing through the South Atlantic Anomaly, for instance.


Satellite failures are much more common in this stronger radiation zone.


It also affects satellites with humans inside, like the International Space Station. Light Flashes, thought to be produced by radiation directly stimulating the retina of astronauts, are reportedly more common when they are flying through the zone.

As the Anomaly is due to the Earth’s magnetic field, and since it’s always moving - including several complete reversals - it probably danced around the planet for the past billion years. It’s curious indeed that such a “special area” would even exist.


And right now, it’s Brazilian.


Researchers build magnetic observatory in the middle of the Atlantic Ocean
by Science Centric
25 November 2008

from Sciencecentric Website

A new Danish observatory on a remote island in the middle of the Atlantic Ocean will provide researchers with new knowledge about the mysterious irregularity of the Earth's magnetic field known as the South Atlantic Anomaly.


The observatory is a partnership between DMI, the Danish Meteorological Institute, and DTU Space, the Danish National Space Institute.

The new geomagnetic observatory is located on the island of Tristan da Cunha and was inaugurated on Friday 14 November by the island's roughly 300 inhabitants and a few of the researchers on the project.


Tristan da Cunha is located right in the middle of the South Atlantic Anomaly,

which is the area where the Earth's magnetic field is weakest.

Danish National Space Centre


Tristan da Cunha is the remotest inhabited island in the world and is also located right in the middle of the South Atlantic Anomaly, which is the area where the Earth's magnetic field is weakest.


This makes it incredibly interesting for the Danish researchers, who are working to understand the Earth's magnetic field and the way in which it affects satellites, for example.

'Until now, Denmark has mostly been involved in projects that measure the magnetic field from space, with the Orsted satellite and the future Swarm satellite mission, as well as the measuring stations in Greenland,' says Professor Nils Olsen of DTU Space.


'With the observatory on Tristan da Cunha, we will have a measuring station in the Tropics right in the middle of the South Atlantic Anomaly, where the strength of the magnetic field is only half as high as in Denmark.'

At present the strength of the Earth's magnetic field is decreasing by 5% every hundred years and researchers do not know why or what the consequences will be.


In the South Atlantic Anomaly, the strength of the magnetic field is decreasing ten times as fast and the measuring station will therefore also give the researchers the opportunity to learn more about the consequences of the global weakening of the magnetic field.

The magnetic field protects the Earth from radiation from space and the area around the South Atlantic Anomaly is therefore very poorly protected. In the Anomaly, the radiation belts that surround the Earth, the van Allen belts, are very close to the surface of the Earth.


This is, among other things, significant to satellites, which suffer by far the majority of faults when they fly through this area.

'Opening the observatory is a milestone in our research,' says senior researcher Juergen Matzka from DMI, who is heading the project.


'Finding a suitable location for the cabin on the island was a major logistical challenge, and we had a lot of help from South African colleagues and the French firm of engineers EnviroConsult. The cabin is also built exclusively of wood and brass in order not to disturb the magnetic measurements.'

Shipping instruments to the island is no mean feat, as Tristan da Cunha is six days' sailing from Cape Town, and there is no port or airport on the island.

Air France 447 electrical problems and the South Atlantic Anomaly

by Tony Pann
Baltimore Weather Examiner
June 4, 2009
from Examiner Website

The Bermuda Triangle and missing aircraft may seem like science fiction, but there is a well documented region off of the coast of Brazil that contains highly charged particles.


This area is known as the South Atlantic Anomaly and is avoided at all costs by orbiting satellites. NASA satellites that do travel in the region are shut down, or go into SAFE mode to avoid damage while passing over the Atlantic between Brazil and Africa.


ROSAT image of South Atlantic Anomaly.

Air France 447 flight path circled in black.


The electrical field around earth protects us from cosmic rays.


There are two bands that trap highly charged particles circle the earth. The protons trapped near the surface is in this region called the Van Allen Belt. This radiation can cause all sorts of malfunctions in spacecraft electronics. In fact, the Geiger counter used to measure cosmic rays on Explorer 1 in 1958 stopped functioning because it was overloaded by radiation!

So what is the connection to Air France flight 447? This is where the highly technical science could put some to sleep.


While this flight path is used by commercial pilots without incidence daily, there is the possibility that one of these tropical thunderstorms tapped into the electric field nearby. The Inter Tropical Convergence Zone is know for some of the most violent thunderstorms on the planet.


With cloud tops over 50,000 feet and violent updrafts of 100 mph, there was a tremendous amount of electricity generated. My friend, a commercial pilot, tells me that lightning can be constant in these storms.


So I pose this question for the flight experts and astrophysicists:

Could flight 447 have been affected by a rare sequence of events including a direct lightning strike, extreme proton charge from the South Atlantic Anomaly, and then left defenseless as the storm and G-Forces in the violent up and downdrafts tore the fuselage apart?

For more see below images:

Although most of our scientific equipment is pointed towards the sky (satellites, telescopes etc,) to measure the Suns activity and its effect on our magnetic field, ionosphere, stratosphere, and as of late our weather (see equation): Equation: Sunspots => Solar Flares => Magnetic Field Shift => Shifting Ocean and Jet Stream Currents => Extreme Weather and Human Disruption

Ground trace of a single GALEX orbit. The particle flux associated with the SAA is modeled (blue = low to red=high). The red line is the night side of the orbit, the day side is white. The high voltage supply on the detectors are not ramped until after exiting the SAA. The viewing cones of the two ground stations are also displayed. A contact with the Hawaii station is possible on this orbit.






Count rate of protons and electrons greater than 0.5 MeV in low Earth orbit measured by the NASA/SAMPEX satellite.




Most of the proton belt is about 12001300 kilometers high, but it dips down as low as 200300 kilometers off the lower coast of Brazil, creating a phenomenon known as the South Atlantic Anomaly. At certain altitudes, the South Atlantic Anomaly is bigger than Brazil itself.

Did Air France Flight 447 travel on the edge of the South Atlantic Anomaly and get a rare impact on their electrical systems from a violent thunderstorm?




Lightning blamed for missing Air France Flight 447
Initial search for Air France Flight 447

An article by Rich Battros from 2005 in asked the question about whether airlines have been notified?


He cites the following incidents as a result of the Van Allen Belts:

United Airlines reported high frequency (HF) communications losses and solar radiation storms which caused planes to be diverted to less dangerous routes. Rerouting and general delays are costly to the airlines. One example of that was a storm that caused a flight to be diverted from a polar route, requiring additional fuel at Tokyo and extending the flight by 5 hrs 30 min.

During another period, 25 flights were flown on less than optimal polar routes due to HF communications problems. Northwest Airlines diverted a Detroit-Beijing flight to a non-polar route due to both HF communications problems (radio blackout) and a solar radiation storm, forcing an unscheduled stop at Fairbanks for fuel.


This route change resulted in an approximately 3 hour delay and $100,000 cost to NWA, plus the inconvenience and loss attendants upon disrupting the travel of passengers.

The Director of Flight Operations of Continental Airlines reported that they diverted their daily flight for the second day in succession based on the S3 level of solar radiation storm.


The direct impact was 2 hours of extra flight time and additional associated costs.


South Atlantic Anomaly and South Georgia Magnetic Observatory

from BGS Website


Why is BGS re-establishing a magnetic observatory on South Georgia?
The South Georgia observatory will plug a significant gap in the global network of magnetic observatories.


In particular South Georgia observatory will allow better monitoring of the South Atlantic Anomaly and of changes occurring deep within the Earth. By establishing the new observatory, BGS will re-start continuous magnetic observations in South Georgia, last carried out in 1982.

What is the South Atlantic Anomaly?
The Earth’s magnetic field, generated deep within the planet, is a shield against particle radiation from space.


In the South Atlantic this shield is much weaker than elsewhere across the globe and radiation from space therefore penetrates deeper into the atmosphere. This region is known as the South Atlantic Anomaly (SAA) and the radiation in the SAA is a known hazard to satellites, spacecraft and high-altitude aircraft.
Monitoring changes in magnetic field

The radiation input into the atmosphere depends on the Sun’s magnetic and radiation activity and the geometry (or ‘shape’) of the Earth’s magnetic field. So, understanding the space environment, particularly during magnetic storms, is important.


Equally important is understanding any changes over time in the magnetic field observed across the surface of the Earth - see also Long-term monitoring of the Earth’s magnetic field.


A magnetic reversal in progress?
The South Atlantic Anomaly (SAA) is known to be growing in extent and spreading westwards from South Africa, as the Earth’s internal magnetic field rapidly weakens in this region.


This may be early evidence of a forthcoming reversal in the direction of the Earth’s internal magnetic field. We do not know in detail precisely what occurs during such reversals, including the changes observed in the magnetic field and the time a reversal takes to complete. However these factors are important in knowing where the radiation risk may be increased and how the atmosphere might respond.

Earth’s magnetic field has had many highs, lows and reversals in its past. The last reversal was around 800,000 years ago. So the Earth is known to be able to re-generate its field and has done so during human pre-history.


Understanding the development of the SAA may therefore be significant in understanding the reversal process and its impact on life and the natural environment.


New South Georgia Magnetic Observatory
By establishing a magnetic observatory on South Georgia BGS geomagnetists will specifically help to develop our understanding of the SAA by:
Joined up monitoring

Directly observing changes in the SAA in a region (mid Atlantic Ocean) poorly covered by permanent magnetic observatories. In the middle of the ocean only Ascension Island, Tristan da Cunha and St Helena observatories can provide monitoring of the magnetic field and its changes. We need to better relate observations of the SAA made separately on the land masses of Africa and South America.


South Georgia observatory will therefore be a key addition to this small network of observatories.


Improving predictions
Providing new data to construct better mathematical models of the magnetic field.


Such models can be used to infer how the flow of liquid iron in the outer core of the Earth is changing. This fluid flow sustains our magnetic field and forecasting how it changes in time will help improve predictions of future change in the SAA.
Understanding the complete ‘Earth System’

Promoting collaboration between space scientists, concerned with Earth’s space environment, and geoscientists, concerned with Earth’s other environments.


There are major communities of these researchers both in the UK and internationally and the expertise of both space- and geo-scientists are needed to fully understand the complete ‘Earth system’.


Measuring, monitoring and modeling the Earth’s magnetic field is a key aspect of this understanding and that is BGS’ contribution to this Endeavour.


Image comprising a series of pictures stitched to show Myviken Bay

looking along the Bore Valley from the North, South Georgia.

British Antarctic Survey © NERC


South Georgia





2011 Earthquakes Mid Atlantic Ridge




Earthquakes 2010-2011 Mid Atlantic Ridge:

  • Rectangular Grid Search

  • Latitude Range: -70 to 10

  • Longitude Range: -80 to 40

  • Number of Earthquakes: 532





Earthquakes 2010 Mid Atlantic Ridge:







Earthquakes 2009 Mid Atlantic Ridge: