ICAO Space Weather (SWX) Information System

Effective from November 2019. However, some information in this summary may change at times and updates will be issued as and when required.

Space weather is a consequence of the behaviour of the Sun, the nature of Earth’s magnetic field and atmosphere, and our location in the solar system. There are various phenomena that originate from the Sun that can result in space weather storms. Outbursts from huge explosions on the Sun - Solar Flares and Coronal Mass Ejections (CME) - send space weather storms hurling outward through our solar system. The Sun also emits a continuous stream of radiation in the form of charged particles that make up the plasma of the solar wind.

From an operations perspective, space weather events occur when the Sun causes disruptions to aviation communications, navigation and surveillance systems, radiation-sensitive electronics and elevates radiation dose levels at flight altitudes. Space weather events may occur on short time scales, with the effects occurring from seemingly instantaneous to a few days hence.

Space weather advisories for international air navigation address particular types of disturbances, such as solar radiation storms, geomagnetic storms, ionospheric storms, and solar flares. These advisories enable operators to maintain awareness of potential hazards and to formulate alternative plans should the impending conditions be of a magnitude and/or type that could disrupt normal operations.

Space weather for aviation impacts on communications, navigation, surveillance, radiation-sensitive electronics, and human exposure. The impacts may include:

  • Unexpected loss of communications;
  • HF voice and HF data link, i.e. Controller Pilot Data Link Communications (CPDLC), on routes where HF is employed;
  • Poor or unusable performance of L-band SATCOM.
  • Degraded performance of navigation and surveillance that rely on GNSS;
  • Automatic Dependent Surveillance – Broadcast (ADS-B) and/or Automatic Dependent Surveillance – Contract (ADS-C) anomalies;
  • Sporadic loss-of-lock of GNSS, especially near the equator, post- sunset.
  • Unanticipated non-standard performance of on-board electronics.
  • Issues related to radiation exposure by aircrew and passengers.

Global centres

ACFJ Consortium - Australia, Canada, Japan & France

Two centres – Melbourne, Australia:  will issue HF Advisories; and Toulouse, France: will issue all other SWX advisories.

PECASUS Consortium - Austria, Belgium, Cyprus, Finland, Germany, Italy, Netherlands, Poland and the United Kingdom

Lead centre in Finland supported by UK (backup) and Belgium (data hub).

United States: Centre based in Boulder, Colorado, USA

Regional centres

1.      China/Russian Federation consortium (may become a global centre in the future)

2.      South Africa

Operation of the global centres

Each of the three global centres will operate for a two-week period every six weeks and when not active they will operate as a backup centre or secondary backup centre for two-weeks each respectively.  This is referred to as a rotational (or roster) arrangement.

SWX advisories are issued when impacts to HF communications, communications via satellite, GNSS-based navigation and surveillance systems, or heightened radiation occurs or is expected to occur.

The advisory message informs users of:

  • The type of impact;
  • The expected onset, or if the event is already in progress;
  • The duration of the event;
  • A generalized description of the spatial extent affected for the next 24 hours;
  • A description of the severity of the impact in moderate (MOD) or severe (SEV) categories.

Forecasts included in SWXA are for 6, 12, 18 and 24 hours beyond the observed time, i.e., +6 HR, +12 HR, +18 HR and +24 HR.

SWX SIGMETs will not be issued by MWOs.

SWXA for GNSS and HFCOM effects

SWX ADVISORY
DTG: 20161108/0100Z
SWXC: DONLON*
ADVISORY NR: 2016/2
NR RPLC: 2016/1
SWX EFFECT: HF COM MOD AND GNSS MOD
OBS SWX: 08/0100Z HNH HSH E18000 – W18000
FCST SWX +6 HR: 08/0700Z HNH HSH E18000 – W18000
FCST SWX +12 HR: 08/1300Z HNH HSH E18000 – W18000
FCST SWX +18 HR: 08/1900Z HNH HSH E18000 – W18000
FCST SWX +24 HR: 09/0100Z NO SWX EXP
RMK: LOW LVL GEOMAGNETIC STORMING CAUSING INCREASED AURORAL ACT AND SUBSEQUENT MOD DEGRADATION OF GNSS AND HF COM AVBL IN THE AURORAL ZONE. THIS STORMING EXP TO SUBSIDE IN THE FCST PERIOD. SEE WWW. SPACEWEATHERPROVIDER.WEB 
NXT ADVISORY: NO FURTHER ADVISORIES

SWXA for RADIATION effects

SWX ADVISORY
DTG: 20161108/0000Z
SWXC: DONLON*
ADVISORY NR: 2016/2 NR
RPLC: 2016/1
SWX EFFECT: RADIATION MOD
FCST SWX: 08/0100Z HNH HSH E18000 – W18000 ABV FL 350
FCST SWX +6 HR: 08/0700Z HNH HSH E18000 – W18000 ABV FL 350
FCST SWX +12 HR: 08/1300Z HNH HSH E18000 – W18000 ABV FL 350
FCST SWX +18 HR: 08/1900Z HNH HSH E18000 – W18000 ABV FL 350
FCST SWX +24 HR: 09/0100Z NO SWX EXP
RMK: RADIATION LVL EXCEEDED 100 PCT OF BACKGROUND LVL AT FL350 AND ABV.THE CURRENT EVENT HAS PEAKED AND LVL SLW RTN TO BACKGROUND LVL. SEE WWW.SPACEWEATHERPROVIDER.WEB
NXT ADVISORY: NO FURTHER ADVISORIES

SWXA for HFCOM effects

SWX ADVISORY 

DTG: 20161108/0100Z

SWXC: DONLON*

ADVISORY NR: 2016/1

SWX EFFECT: HF COM SEV 

OBS SWX: 08/0100Z DAYLIGHT SIDE

FCST SWX +6 HR: 08/0700Z DAYLIGHT SIDE

FCST SWX +12 HR: 08/1300Z DAYLIGHT SIDE

FCST SWX +18 HR: 08/1900Z DAYLIGHT SIDE

FCST SWX +24 HR: 09/0100Z NO SWX EXP

RMK: PERIODIC HF COM ABSORPTION AND LIKELY TO CONT IN THE NEAR TERM. CMPL AND PERIODIC LOSS OF HF ON THE SUNLIT SIDE OF THE EARTH EXP. CONT HF COM DEGRADATION LIKELY OVER THE NXT 7 DAYS. SEE WWW. SPACEWEATHERPROVIDER.WEB

NXT ADVISORY: 20161108/0700Z

* fictitious location

 

FNXX01 KWNP 020100
SWX ADVISORY
DTG: 20190502/0100Z
SWXC: DONLON*
ADVISORY NR: 2019/59
NR RPLC: 2019/58
SWX EFFECT: GNSS MOD
OBS SWX: 02/0100Z HNH HSH E18000-W18000
FCST SWX + 6 HR: 02/0700Z HNH HSH E18000-W18000
FCST SWX + 12 HR: 02/1300Z HNH HSH E18000-W18000
FCST SWX + 18 HR: 02/1900Z NO SWX EXP
FCST SWX + 24 HR: 03/0100Z NO SWX EXP
RMK: IONOSPHERIC STORM CONTINUES TO CAUSE LOSS-OF-LOCK OF GNSS IN AURORAL ZONE. THIS ACTIVITY IS EXPECTED TO SUBSIDE IN THE FORECAST PERIOD
NXT ADVISORY: 20190502/0700Z=

1. FNXX01 KWNP 020100 WMO Header (FNXXii, WMO location indicator of SWXC, UTC date-time of issue of the message). The message header can be ignored by pilots.
2. SWA Advisory Type of message (Space Weather Advisory)
3. STATUS (conditional – may not be included) STATUS indicator only included if needed - either test (TEST) or exercise (EXER)
4. DTG: 20190502/0100Z DTG (Date, time group): Date and time of the SWX Advisory message (yyyymmdd/nnnnZ) – in this case: 0100 UTC on 2nd May 2019.
5. SWXC Name of Space Weather Centre issuing the product*.
6. ADVISORY NR Year in full and unique message number, in form yyyy/nnn.
7. NR RPLC Number of the previously issued advisory being replaced. In the form of yyyy/nnn.
8. SWX EFFECT Effect and intensity of space weather phenomenon:
  • high frequency radio communications (HF COM);
  • global navigation satellite systems (GNSS) based navigation and surveillance systems;
  • radiation effects on avionics and/or human health (RADIATION); and
  • satellite communications (SATCOM).
And either MODerate or SEVere.
9. OBS (or FCST) SWX Date and time (in UTC) and description of horizontal extent** of observed or forecast space weather phenomenon.
10. FCST SWX +6HR: 02/0100Z HNH HSH E18000-W18000

6-Hour forecast to stated OBS (or FCST) time of horizontal extent** of space weather event.

Or, indication that the SWX phenomenon is no longer expected (NO SWX EXP) or the forecast is not available (NOT AVBL)

In this case, MOD GNSS impact is expected from E18000-W18000 in the latitude regions HNH (from N9000 – N6000) and HSH (from S6000 – S9000).

11. FCST SWX +12HR As for element 10, but for a 12-Hour forecast to stated OBS (or FCST) time.
12. FCST SWX +18HR As for element 10, but for an 18-Hour forecast to stated OBS (or FCST) time.
13. FCST SWX +24HR As for element 10, but for a 24-Hour forecast to stated OBS (or FCST) time.
14. RMK Free-text comment on expected effect and its continuity
15. NXT ADVISORY: 20190502/0700Z Date and time of next SWX Advisory message (yyyymmdd/nnnnZ) – in this case: 0700 UTC on 2nd May 2019. Otherwise, if no further advisories are expected - NO FURTHER ADVISORIES

* Note DONLON is a fictional centre.
** Note that there is no vertical extent description possible for SWX, except for radiation events.

Element to be forecast    Range  Resolution
Flight level affected by radiation    FL250 – FL600  30
Longitude for advisories (degrees)    0000 – 1800 (E & W)  15
Latitude for advisories (degrees)    EQ – 900 (N & S)  10
Latitude bands for advisories  (degrees and minutes)       High latitudes northern   hemisphere (HNH)  N9000 – N6000  30     
 Middle latitude northern   hemisphere (MNH)  N6000 – N3000
 Equatorial latitudes northern   hemisphere (EQN)  N3000 – N0000
 Equatorial latitudes southern   hemisphere (EQS)  S0000 – S3000
 Middle latitudes southern   hemisphere (MSH)  S3000 – S6000
 High latitudes southern   hemisphere (HSH)  S6000 – S9000

The area affected may also be described as DAYLIGHT SIDE, meaning the extent of the planet that is in daylight (used for short wave fadeout events).

  WMO Headers
  TAC Advisory IWXXM Advisory
ACFJ - Australia FNXX01 YMMC LNXX01 YMMC
ACFJ - France FNXX01 LFPW LNXX01 LFPW
PECASUS FNXX01 EFKL LNXX01 EFKL
USA FNXX01 KWNP LNXX01 KWNP

SWX Advisories will be disseminated to users via the ROBEX distribution mechanisms rather than directly to end users via AFTN/AMHS.

SWXCs will send advisories to their National OPMET Centre (NOC), who will forward the message to their Regional OPMET Centre (ROC). The ROCs will forward the message to the Inter-regional OPMET Gateway (IROGs) and other regional ROCs (who will make SWXA available to NOCs within their area of responsibility). The IROGs will distribute the message to their neighbouring IROGs and internet-based services (SADIS and WIFS).

Users will access Space Weather Advisories through their normal national aviation briefing service but it should be noted that airlines may request their NOCs to deliver SWXAs directly to the airline, via AFTN/AMHS, like other OPMET.

The ICAO Global Space Weather Service does not specifically define the operational responses to space weather events and the receipt of SWA.  Such responses are the responsibility of aircraft operators, which may choose to have operational procedures in place in order to be ready in case of space weather events.

The following general guidelines may however be useful:

  1. Depending on the intensity of the phenomena, aircraft operators might choose to fly less exposed routes, or delay their flights until the phenomena have abated.
  2. They might also wish to use alternate means of communication and/or navigation.
    1. HF absorption on the daylight side of Earth, in equatorial areas, and in polar areas tend to affect the lowest frequencies in the HF band. The upper part of the HF band might be less affected.
    2. The arrival of magnetic material may result in physical processes that may impact the upper part of the HF band (Maximum Usable Frequency depression) from hours to days. In that case, the lower HF frequencies might be less affected.
  3. Impacts on GNSS may result in reduced availability of specific GNSS services. This may require, during rare and particularly strong events, the use of alternate navigation means to GNSS SBAS and/or GNSS GBAS approaches with vertical guidance (i.e. for 3D instrument approaches down to LPV minima and/or to GLS minima). For enroute, terminal and 2D instrument approaches, it is unlikely that space weather induced positioning errors would exceed lateral GNSS guidance margins. GNSS and SATCOM signals may also be degraded (amplitude and/or phase signal scintillations) in all phases of flight, to the point where the signals can no longer be processed by receivers, which lose lock.
  4. Flying at lower altitude and/or latitude decreases radiation aboard aircraft. It should be noted however that solar events which are able to accelerate particles enough for them to result in a significant radiation increase at aircraft altitudes are rare. Since 2000, the 4 radiation events which led to a significant radiation increase at aircraft altitudes occurred on 14 July 2000, 15 April 2001, 20 January 2005, and 13 December 2006. During those events, it is estimated that the radiation dose received during a long-haul flight reaching high latitudes was equivalent to that usually received (from galactic cosmic rays) during a couple of similar long-haul flights.
AFTN Aeronautical Fixed Telecommunication Network
AMHS ATS Message Handling System
CME Coronal Mass Ejections
EQN Equatorial latitudes northern hemisphere (N30.00 – N00.00)
EQS Equatorial latitudes southern hemisphere (S00.00 – S30.00)
GNSS Global navigation satellite system-based navigation and surveillance (degradation)
HF COM High frequency communications (propagation, absorption)
HNH High latitudes northern hemisphere (N90.00 – N60.00)
HSH High latitudes southern hemisphere (S60.00 – S90.00)
IROG Inter-regional OPMET Gateway
IWXXM ICAO Meteorological Information Exchange Model
MNH Middle latitudes northern hemisphere (N60.00 – N30.00)
MSH Middle latitudes southern hemisphere (S60.00 – S90.00)
MWO Meteorological Watch Office
NOC National OPMET Centre
OPMET Operational Meteorological Information
RADIATION Radiation at flight levels (increased exposure)
ROBEX Regional OPMET Bulletin Exchange
ROC Regional OPMET Centre
RODB Regional OPMET Data Bank
SADIS Secure Aviation Data Service
SATCOM Communications via satellite (propagation, absorption)
SWX Space Weather
SWXA Space Weather Advisory
SWXC Space Weather Centre
TAC Traditional Alphanumeric Code
WIFS WAFS Internet File Service

For further information on space weather, see the Australian Bureau of Meteorology’s brochures on space weather and space weather advisories. The advisories are expected to be issued, when necessary, from 07 November 2019.

Australian Bureau of Meteorology – Space weather(external link)
Australian Bureau of Meteorology – Space weather advisories(external link)

For more detailed information, including how MOD and SEV SWX intensities are defined, see:
ICAO Doc 10100 - Manual on Space Weather Information in Support of International Air Navigation(external link).

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