Page 20 - 2018-Issue1

Space Weather 101

BY CAPTAIN JAMES GASKELL

The goal of this article is to familiarize flight crews with space weather and its relevancy on our working environment. This article
includes information given on the National Oceanic and Atmospheric Administration (NOAA) Space Weather prediction Centre
(SWPC)website: http://www.swpc.noaa.gov/ and the United Kingdom Met Office Space Weather Operations Centre (MOSWOC)
website: https://www.metoffice.gov.uk/space-weather.
Space Weather describes changing environmental conditions in near-Earth space. Magnetic fields, radiation, particles and matter
ejected from the Sun can interact with the upper atmosphere and the Earth’s magnetic field to produce numerous effects. The very
highest energy particles come from our Galaxy or even beyond, but are rare. Less energetic Galactic Cosmic Rays are the origin of the
majority of our exposure whilst airborne.
The NOAA SWPC of the United States, as well as the UK Met Office, produce warnings and forecasts of Radio Blackouts (R1-5),
Solar Radiation Storms (S1-5) and Geomagnetic Storms (G1-5). These and their effects are defined by NOAA on their website. They
can also be seen on the figure at right.

RADIO BLACKOUTS
NOAA SWPC receives information from Geostationary Orbit Environmental Satellites (GOES). The largest solar flare seen by
GOES for ten years occurred at about 0600 UTC on 6th September 2017. The flux on the GOES satellite was 9.3 times the threshold
for X flares. This gave an R3 warning and a limited radio blackout on the sun-lit side of the Earth for an hour. Flares are categorized
in increasing flux of soft X rays received at a GOES satellite as A, B, C, M, and X. Only M and above trigger radio blackout warn-
ings. The X-rays travel at the speed of light, so travel time is only about 81/2 minutes. Once the X-rays are detected, the effects are
already here, so an alert is issued to notify the onset of an event and the duration of the effects on the Earth’s Ionosphere can be
predicted. These disturbances typically last an hour or so dependent on the flux received. The flares are associated with sunspots,
which are regions with intense magnetic fields on the Sun often many times the size of the Earth.

ISSUE 1 | 2018 InterPilot | The Safety and Technical Journal of IFALPA