Cosmic Ray Monitoring

This page will provide a variety of sources of cosmic ray monitoring in real time. This is required as GCR’s (Galactic Cosmic Rays) do not uniformly hit the surface of the planet as they have usually unique trajectories as they come from a variety of other solar systems in the Universe.

Australia has a few key monitoring stations for Cosmic Rays in mainly remote locations. The following are dedicated Muon Detectors.

Hobart Tasmania.

Mawson Antarctica

From SWS BOM – Cosmic Ray Data Applications to Space Weather Forecasting ( THIS DEVICE IS FAULTY at the moment.)

Forbush Decrease Event

The magnetic fields entrapped in and around coronal mass ejections exert a shielding effect on the galactic cosmic radiation (GCR) which is detected by the neutron monitors. This causes a reduction in the count rate from the monitor. The reduction is typically from about 3 to 20%. The reduction occurs typically over a timescale of several hours to a few days.

Forbush decrease events must be at least 3% for a Forbush decrease alert to be issued. The reduction in the GCR due to a coronal mass ejection (CME) is dependent upon:

  • the size of the CME
  • the strength of the magnetic fields in the CME
  • the proximity of the CME to the Earth

Because the reduction is dependent on three factors (rather than one), it is difficult to forecast the time from a Forbush Decrease to the arrival of a coronal mass ejection at the Earth. However, previous experience in SWS is that a Forbush Decrease is a reliable indicator of a geomagnetic storm, and that warning times of up to 24 hours or more may be made. The Forbush Decrease can be used in conjunction with other indications (eg coronagraph imagery) to further confirm the event. Detection of a Forbush Decrease is in use at the SWS ASFC for assistance in prediction of geomagnetic storms.

Ground Level Event

In this case, an increase in detector count rate is not due to galactic cosmic radiation, but to the addition of solar cosmic (high energy) radiation (solar cosmic rays) from an previous solar particle event (SPE). The increase in the count rate may be from about 3 to 10,000%. The increase from ambient to peak count rate may take only a few minutes (fast high energy event) to an hour or two (slow and usually lower energy event). The return of the count rate to galactic cosmic ray background may take anywhere from a few hours to a few days.

Nagoya Japan


Olulu Finland

Hours / Month / Years