Radiation Expert Group and Servicefor a global space weather service to support civil aviation

E. De Donder (1), M. Latocha (2), P. Beck (2), M. Dierckxsens (1), N. Crosby (1), S. Calders (1)

(1) Royal Belgian Institute for Space Aeronomy (BIRA-IASB)(2) Seibersdorf Laboratories (SL)

Abstract. The Pan-European Consortium for Aviation Space weather User Services (PECASUS) consortium has been created in response to the call from the International Civil Aviation Organisation (ICAO) to provide a Global SpaceWeather Information Service. The requested service focuses on the dissemination of warning messages ('advisories') towards aviation actors and corresponds to extreme space weather events with impact on aviation GNSS systems,HF communication, satellite communications and radiation levels at flight altitudes.The Expert Group for RADiation (EG RAD) within the PECASUS consortium is coordinated by BIRA-IASB within the STCE (Solar-Terrestrial Centre of Excellence) in collaboration with Seibersdorf Laboratories. We present here the keyproducts that are used to put duty officers on alert and to generate the input for the radiation advisory messages.

Acknowledgements:

We acknowledge the National Observatory of Athens which hosts the HESPERIA UMASEP-500 tool (https://www.hesperia.astro.noa.gr/images/umasep/realtime/result500.gif) (HESPERIA project, Grant

Agreement No 637324, European Union's Horizon 2020 research and innovation programme) and ANeMoS, Seibersdorf Laboraties, BIRA-IASB for making their products (resp. the GLE Alert Plus service and

access to the NM database, the AVIDOS dose rate maps and COMESEP) available through the ESA SSA Service Network in the frame of the ESA Contract No. 40001122444/14/D/MRP.

The radiation environment at aviation altitudes is shaped mainly by Galactic Cosmic Radiation (GCR) and occasional Solar Energetic Particle (SEP) events, both phenomena comprised of high energetic particles(mainly protons) that interact with Earth's atmosphere and generate secondary particles. High energy protons entering the funnel-like cusps in the Earth's magnetic field above the polar caps impact not onlythe health of crew and passengers, but also electronic devices and HF communications. When, due to a SEP event, an elevated radiation level is recorded on Earth it is known as a Ground Level Enhancement(GLE).

In EG RAD, radiation conditions at aviation altitudes are assessed with the AVIDOS tool. AVIDOS provides nowcast of radiation exposure due to GCRs and SEPs. Every 5 minutes, a maximum and a minimumexpected effective dose rate is produced at any geographical position (5°x5° lon-lat grid) and in an altitude range from 8 km to 15 km. The automated AVIDOS procedure makes use of near real-time (NRT)observations on Ground-Level Events (GLE) (provided by ANeMoS GLE alert + service) and NRT 1-min data from the Neutron Monitor (NM) in Oulu. AVIDOS dose estimations have been carefully validated bycomparisons with Tissue Equivalent Proportional Counters and have good correspondence with the measurements (ref. Latocha, M. and Beck, P., 2016, doi:10.1109/RADECS.2016.8093138)

In addition to AVIDOS, several tools are consulted as indicators for a possible increase of the radiation exposure and used to warn the forecasters and to increase their alertness.The COMESEP “SEPForecast” tool predicts the probability of occurrence and the expected strength (level) of radiation storms with proton energies > 10 MeV and > 60 MeV following the observation of a soft X-ray flare (M or X class)provided by the COMESEP Flaremail alert tool.The HESPERIA UMASEP-500 tool is a real-time predictor of >500 MeV SEP and GLE events. It correlates GOES soft X-ray and differential proton fluxes above 500 MeV energies to detect magnetic connectivity along which the solarprotons arrive.The GLE Alert + service shows the general GLE alert level as well as a recent timeline of the number of neutron monitor stations that are in alert mode (i.e. have enhanced levels of count rates). It also provides an indication when theradiation levels start to decrease again.

A space weather advisory for radiation is issued when heightened radiation occurs. The severity of the radiationimpact, moderate (MOD) or severe (SEV), is defined in terms of the effective dose rate (in micro-Sievert/hour).The ICAO thresholds are currently set atMOD advisories are only issued when the MOD threshold is reached at FL460 (~14 km) and below. SEV advisoriesare issued when the SEV threshold is reached at any flight level.

EG RAD WORKFLOW

GOES/HEPAD proton fluxes

GOES/X-ray fluxes

SDO/AIA images

SOHO/LASCO images

NM data

HESPERIA UMASEP- 500

COMESEP SEP

ANeMoS GLE Alert +

AVIDOS ADVISORY

>30 (MOD) >80 (SEV)

(communication header)

SWX ADVISORY

DTG: 20190419/0300Z

SWXC: PECASUS

SWX EFFECT: RADIATION MOD

ADVISORY NR: 2019/2

FCST SWX: 20190419/0300Z HNH HSH E18000-W18000 ABV FL460

FCST SWX + 6 HR: 20190419/0900Z HNH HSH E18000-W18000 ABV FL460

FCST SWX + 12 HR: 20190419/1500Z HNH HSH E18000-W18000 ABV FL460

FCST SWX + 18 HR: 201970419/2100Z NO SWX EXP

FCST SWX + 24 HR:

RMK: RADIATION AT AIRCRAFT ALTITUDES ELEVATED BY SMALL ENHANCEMENT JUST ABOVE PRESECRIBED THRESHHOLD. DURATION TO BE SHORT-LIVED. SEE WWW.PECASUS.EU

NXT ADVISORY: NO FURTHER ADVISORIES

SPACE WEATHER ADVISORY for RADIATION

NOTIFICATIONS ON POTENTIAL ENHANCEMENTS in DOSE RATES

RADIATION DOSES at FLIGHT ALTITUDES