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What You Need To Know About Solar Weather

by John White |

If you fly internationally from North America to Asia, whether as a pilot or a passenger, your flight will be affected by solar weather, and in this post I will explain what you need to know about solar weather (also known as space weather) . In fact, even if you don’t make these kinds of trips, you should still be aware of solar weather and its potential effects on you, your family and on our planet. As you may have already guessed, solar weather is about the effect activity on the sun has to life here on earth.

Solar Weather Data Collection and Prediction Resources

Since the early 1800s the United States military have been recording weather observations regularly as part of their medical studies. By 1870 Congress established the U.S. Army Signal Corps which was replaced by the National Weather Service in 1890. Today the Space Weather Operations Branch (SWO), a joint operation of the U.S. Air Force and the National Oceanic and Atmospheric Administration (NOAA), is responsible for monitoring, analyzing and forecasting the environment between the Sun and the Earth. Through a system of ground based and satellite sensors the SWO collects data to predict solar and geomagnetic activity that can affect activities here on Earth or in near-Earth space. Solar weather forecasters then use that date to issue worldwide warnings of impending dangerous solar events.

Solar Geophysical Phenomena Activity Of The Sun

The solar activity phenomena monitored fall into 4 categories:
  1. Solar Phenomena
  2. Solar Radiation Hazards
  3. Geomagnetic Activity
  4. Solar Radio Interference
These phenomena can affect a wide variety of Earth-Space activities, including…
  • High altitude polar flights by aircraft
  • Global Positioning System (GPS) navigation capabilities
  • Electric power grid distribution operations
  • High frequency radio communications
  • Long line telephone communications
  • Pipeline operations
  • Satellite operations
  • Space activities
just to name a few.

Solar Wind, Solar Flares and Sunspots

The solar wind comes off of the sun at about 1 million miles per hour, and while it travels in all directions the solar wind speed is not uniform. It can be impacted by a number of things including coronal holes and magnetic clouds. Solar flares are sudden, rapid and intense eruptions of plasma from the surface of the sun out into space. Sunspots are temporary phenomena on the sun which appear as dark spots and which are caused by very strong magnetic activity on the photosphere. Because they are roughly 30% cooler than the surrounding material of the photosphere they appear as dark spots. Solar flares and coronal mass ejections occur around groupings of these sun spots. Sunspots have an irregular pattern of roughly 11 years, although from time to time the cycle lasts much longer.

The Impact of Electromagnetic And Solar Radiation To Flying

Pilots who fly polar routes need to be familiar with 3 very important scales regarding solar radiation, radio blackout and geomagnetic storms. Each scale has a series of ratings depending upon the severity of the risk. The Solar Radiation Storm Scale is as follows:

S5 (Extreme) – This level indicates a high radiation hazard to jet aircraft with radiation levels equivalent to 100 chest x-rays, can cause loss of some satellite data and eliminates high frequency (HF) radio communication in polar regions.

S4 (Severe) – This level indicates a radiation hazard to jet aircraft with radiation levels equivalent to 10 chest x-rays, satellite orientation problems and a blackout of HF radio communication at the polar cap for several days.

S3 (Strong) – This level presents a radiation hazard to passengers equivalent to 1 chest x-ray, a temporary upset to exposed satellite components and degraded HF radio communication in polar regions.

S2 (Moderate) – This level presents infrequent satellite upset events and a slight effect on HF radio communication in the polar cap region.

S1 (Minor) – This level has a slight effect on HF radio communication in the polar region.

The Radio Blackout Scale is as follows:

R5 (Extreme) – This level presents a complete HF radio communication blackout and navigational outages on the entire sunlit side of Earth for hours.

R4 (Severe) – This level presents a one to two hour HF radio communications blackout with minor satellite navigation disruptions.

R3 (Strong) – This level presents a wide area of HF radio communication blackout, loss of radio contact with mariners and aviators for about an hour and low frequency navigation (LORAN) signal degradation.

R2 (Moderate) – This level presents a limited loss of HF radio communication capability with some low frequency navigation signals degraded.

R1 (Minor) – This level presents a minor degradation of HF radio communication capabilities and minor low frequency navigation signal degradation.

The Geomagnetic Storm Scale is as follows:

G5 (Extreme) – This can result in the power grid collapsing, damage to transformers, potential threats to satellites and spacecraft operations, HF radio communication blackout for several days, low frequency navigation signal outage for many hours and the aurora can be seen as far South as the Equator.

G4 (Severe) – This presents voltage stability problems in power systems, satellite orientation problems, induced pipeline currents, HF radio communications sporadic, low frequency signal disrupted and the aurora can be seen as far South as the tropics.

G3 (Strong) – The requires voltage corrections on power systems, false alarms triggered on security systems, increased drag on satellites, low frequency radio navigation problems and the aurora can be seen in the mid-latitudes.

G2 (Moderate) – High latitude power systems are affected, drag on satellites affects their orbits, HF radio communication fades at higher altitudes and the aurora can be seen at latitude 50 degrees or higher.

G1 (Minor) – This will cause minor grid power fluctuations, have a minor impact on satellites and the aurora can be seen at latitude 60 degrees or higher.

Effects On Aircraft Operating Over The Polar Regions

When the Storm Scale for Solar Radiation, Radio Blackout or Geomagnetic Storm levels are 5 or 4 aircraft should not fly in the polar region. When these levels are at 3 aircraft altitude is limited to 31,000 feet or lower. You can learn more about these effects on aircraft operations in Doug Morris’s book From the Flight Deck: Plane Talk and Sky Science. . Until next time keep your wings straight and level Hersch! JetAviator7 ps: Don't forget to sign up for our newsletter "All Things Aviation" here!

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