A National Weather Service unit that monitors solar activity has begun issuing advisories on conditions that could disrupt GPS navigation and high-frequency radio communications or pose a radiation risk to aircraft occupants.
The NWS’s Space Weather Prediction Center was chosen in 2018 by the International Civil Aviation Organization (ICAO) as one of three space weather centers around the world to maintain 24-hour watches and disseminate advisory information “regarding the extent, severity, and duration of the space weather phenomena and supply the advisory information to area aeronautical control centers, flight information centers,” and other users of meteorological data. The other observations will be taken in Australia and France.
The advisory service was scheduled to begin on or about November 7, according to a notice of the service upgrade issued by the NWS.
The advisories will be produced “as conditions warrant,” and once issued will be updated at six-hour intervals “from the nearest hour after the advisory is issued until the space weather phenomena are no longer detected and/or are no longer expected to have an impact,” it said.
Users of ICAO space weather advisories include the NWS, FAA, and international civil aviation authorities, commercial airlines, and private companies, it said.
The format in which the advisories are presented, abbreviations, and examples of advisory messages are included in this product description that the NWS issued in October.
Strong effects of intense space weather on terrestrial communications and navigation are rare, but past events demonstrate that the solar emissions can wreak havoc.
An article in the February 2018 newsletter of the Commission for Aeronautical Meteorology recalled that the “Halloween Storms” of 2003—as an outbreak of significant space weather that fall was known—had a variety of impacts on aviation. On October 28 that year, the FAA “issued their first ever advisory” suggesting a risk to aircraft occupants of excessive radiation doses. Also, the Wide Area Augmentation System (WAAS) “was seriously impacted for a 15-hour period on October 29th and an 11-hour interval on October 30th, essentially rendering the system unusable during that time.”
In September 2017, strong solar flares periodically disrupted HF radio communications, it said, also noting that “communication by Miami air traffic control via HF with aircraft taking oceanic routes around incoming Hurricane Irma was problematic at times, exacerbating an already challenging situation.”