Solar Terrestrial Data
Weather on Earth is highly influenced by events on our sun. Also the amount of solar spots and aurora borealis have a remarkable effect on radio wave propagation.
HF communication frequencies are also used for aircraft crossing Oceanic and other sparse areas where VHF communications falls short due to its line of sight properties. We felt we needed to include solar information so that pilots, using these HF frequencies, can prepare themselves.
To the right you will see the intensity of the Aurora oval over the North Pole. This is the result of solar flares entering the Earths magnetic field. Click the image for more info, or the next link for the South Pole Aurora image.
The information presented here is sourced from other websites so if one or two images do not show up its because they probably could not be retrieved at that time, refreshing this page can help.
Now that the sun is coming out of a solar spot low the effects can eventually be noticed on HF and VHF frequencies where aircraft long range communication takes place. Especially on shortwave frequencies.
Solar Activity
From spaceweather.com: "A solar flare is an explosion on the Sun that happens when energy stored in twisted magnetic fields (usually above sunspots) is suddenly released. Flares produce a burst of radiation across the electromagnetic spectrum, from radio waves to x-rays and gamma-rays."
This radiation is measured by satellites (GOES) and plotted on so called X-Ray Flux plot. To see these plots click on the 5 minute X-ray Flux for a three day overview or on the 1 minute X-ray Flux for a six hour monitor.
NOAA.gov: The GOES X-ray flux plot contains 1 and 5 minute averages of solar X-rays in the 1-8 Angstrom (0.1-0.8 nm) and 0.5-4.0 Angstrom (0.05-0.4 nm) passbands. Data from the SWPC Primary GOES X-ray satellite is shown.
The sun also emits high energy protons during flares, when these particles reach Earth they can block out HF transmissions for polar paths. The next link opens a window with the latest 3 day GOES Proton Flux.
The effects of extreme solar radiation are listed on this NOAA Space Weather Scale. For more information visit the NOAA Space Weather site.
Other solar data is shown below.
Conditions on the Sun |
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HF Radio Propagation |
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The information above can be used to predict radio propagation on HF and VHF, useful for pilots working these frequencies.
Data courtesy of n0nbh.com, hamsql.com and rigreference.com.
In our weather phenomena section we have an explanation on how the Ionosphere reflects radio waves.
