Due to the activity of the Sun on Earth, a “polar cap absorption event” occurred

(ORDO NEWS) — January 13, satellites in near-Earth orbit recorded a pulse of energetic protons from the Sun. As they collided with the Earth, a polar cap absorption event (PCA) occurred:

Shortwave radio signals around the South Pole weakened dramatically. Why? Protons directed by the Earth’s magnetic field into the Antarctic atmosphere ionized the D-layer of the ionosphere.

This disrupted the normal propagation of radio signals at frequencies below ~30 MHz.

The PCA lasted several hours and would have cut off radio communications for any aircraft flying over the South Pole.

PCAs are a big problem when they occur over the North Pole, where ‘great circle’ air traffic is busier.

PCA – A condition in the polar ionosphere in which HF and VHF radio waves are absorbed and LF and VLF radio waves are reflected at lower than normal heights.

PCA events are usually due to strong solar storms that launch energetic protons, which quickly reach our outer atmosphere and cause excess ionization, which distorts the normal refractive properties of the polar ionosphere.


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