Archiv: magnetic poles


05.06.2019 - 20:00 [ Phys.org ]

Earth’s magnetic poles could start to flip. What happens then?

(07.12.2018)

‚The geomagnetic field has been decaying for the last 3,000 years,‘ said Dr. Nicolas Thouveny from the European Centre for Research and Teaching of Environmental Geosciences (CEREGE) in Aix-en-Provence, France. ‚If it continues to fall down at this rate, in less than one millennium we will be in a critical (period).‘

29.04.2019 - 13:21 [ Geophysical Research Letters 35(16) / researchgate.net ]

Magnetic effect on CO 2 solubility in seawater: A possible link between geomagnetic field variations and climate

(August 2008)

Correlations between geomagnetic-field and climate parameters have been suggested repeatedly, but possible links are controversially discussed. Here we test if weak (Earth-strength) magnetic fields can affect climatically relevant properties of seawater. We found the solubility of air in seawater to be by 15% lower under reduced magneticfield (20 mT) compared to normal field conditions (50 mT). The magnetic-field effect on CO2 solubility is twice as large, from which we surmise that geomagnetic field variations modulate the carbon exchange between atmosphere and ocean. A 1% reduction in magnetic dipole moment may release up to ten times more CO2 from the surface ocean than is emitted by subaerial volcanism.

29.04.2019 - 13:15 [ Stanford University ]

ON THE WEAKENING OF THE POLAR MAGNETIC FIELDS DURING SOLAR CYCLE 23

(20. Dezember 2009)

The Sun’s polar fields are currently ∼40% weaker than they were during the previous three sunspot minima. This weakening has been accompanied by a corresponding decrease in the interplanetary magnetic field (IMF) strength, by a ∼20% shrinkage in the polar coronal-hole areas, and by a reduction in the solar-wind mass flux over the poles. It has also been reflected in coronal streamer structure and the heliospheric current sheet, which only showed the expected flattening into the equatorial plane after sunspot numbers fell to unusually low values in mid-2008. From latitude–time plots of the photospheric field, it has long been apparent that the polar fields are formed through the transport of trailing-polarity flux from the sunspot latitudes to the poles.

29.04.2019 - 12:48 [ Nature.com ]

Earth’s magnetic field is acting up and geologists don’t know why

(9. Januar 2019)

The magnetic pole is moving so quickly that it has forced the world’s geomagnetism experts into a rare move.

On 15 January, they are set to update the World Magnetic Model, which describes the planet’s magnetic field and underlies all modern navigation, from the systems that steer ships at sea to Google Maps on smartphones.

29.04.2019 - 12:35 [ British Geological Survey ]

World Magnetic Model (WMM)

The World Magnetic Model (WMM) is a standard model of the core and large-scale crustal magnetic field. It is used extensively for navigation and in attitude and heading referencing systems by the UK Ministry of Defence, the US Department of Defense, the North Atlantic Treaty Organization and the International Hydrographic Organization.

(…)

The WMM is a model of the core and large-scale crustal fields only. However the satellite data contain unwanted signals such as small-scale crustal, external ionospheric and magnetospheric and their induced counterparts. These fields would have added noise to the WMM2015 SV model and could have biased its estimates.

BGS employed two techniques to avoid the contamination caused by external magnetic fields. Firstly we rejected those data most contaminated by these sources, as identified by a combination of local time, geomagnetic indices and solar wind data. ……..