TROPOMAG: Influence of geomagnetic storms on the TROPOsphere dynamics: Can the Earth’s MAGnetic field be considered a proxy of climate changes?
What is the Earth’s Magnetic Field?
The Earth’s magnetic field is generated deep inside the Earth. Its primary source is in the fluid core of the planet. Here, a complex system of electrical currents, fed by heat convection and forced by the Earth’s rotation, gives rise to a magnetic field that reaches the Earth’s surface and extends out into space surrounding our planet.
Like a bubble around the Earth, this magnetic field preserves us from the harmful influences of the charged particles coming from the Sun (called Solar Wind) and of cosmic radiation. It acts like an invisible shield surrounding our planet as a “shell” and it is very important for development and maintenance of the human habitat, as it also prevents the water vapor in our atmosphere from being swept away by the solar wind.
The Earth’s magnetic field intensity is not uniform on the whole surface of the planet and, in particular, the shielding from Galactic Cosmic Rays can be slightly less effective in some regions. For example, in the South Atlantic Anomaly, a wide area between Brazil and the North-Western African coasts where the Earth’s magnetic field intensity is lower than the average mid-low latitude level.
How does the “Space Weather” influence our lives?
The cycle of activity of the Sun is such that, periodically, bursts of radiation and particles are ejected from its surface and reach the Earth. A portion of them can penetrate the shielding of the Earth’s Magnetic Field and excite molecules and atoms of the ionosphere (the uppermost part of our atmosphere).
Such penetration of radiation and particles has the effect of perturbing the electromagnetic signals transmitted from low orbiting satellites to the surface of the Earth thus affecting, for example, the precise timing and positioning provided by the GPS constellation. Moreover, electrical currents are fed in the ionosphere that may perturb the Earth’s magnetic field which, for the induction laws, in turn induces currents at ground (called Geomagnetically Induced Currents) that may damage the power networks, gas/oil pipelines, and railways.
A rather recent discipline called “Space Weather” tries to characterize and possibly forecast the occurrence of the potentially dangerous events originating from the Sun and the interplanetary space.
“Space Weather”, “Meteorological Weather” and “Climate”: Can be they connected?
The potential connection between the Earth’s magnetic field and climate has been subject of debate for decades.
On one hand, there are studies showing how the modulation of the Galactic Cosmic Rays flux by the solar activity affects the formation of clouds and the intensity of thunderstorms (and associated precipitations). On the other hand, the potential connection between the occurrence of ionospheric and geomagnetic storms and variations of the atmospheric pressure has been speculated as well.
TROPOMAG, an institutional project of the Environment Department of INGV, aims at investigating, for the first time, the connection between Space Weather and Climate with a multidisciplinary and multi-instrument approach, concentrating on the Italian volcanic areas of Mt. Etna, Stromboli, Vulcano and Vesuvio, where the atmosphere-ionosphere coupling can be favoured by the uplift of the volcanic particulate, which is often electrically charged and can establish an electromagnetic bridge between the low, neutral atmosphere and the high, charged, ionosphere.
Drawing a more accurate picture of the connections between “Space” and “Meteorological” weather is a first fundamental step towards the investigation of a possible long-term influence of the Earth’s magnetic field on Climate itself. We nowadays have quite reliable models of the Earth’s magnetic field able to represent its evolution in the last centuries and even dare to predict its future behavior: only (by) putting all the pieces of the puzzle together we could try to assess the contribution of the Earth’s magnetic field variations on Climate changes.