HESPERIA-REleASE-Plus

HESPERIA REleASE+ combines the existing HESPERIA REleASE system (the relativistic electron module) with a novel radio module that qualifies type-III radio bursts as a precondition for a proton alert with the aim of reducing specific sources of false alarms. Type-III radio bursts, that are produced by electron beams accelerated in solar eruptive events travelling outward through the corona along open magnetic flux tubes, are used as an independent early evidence of particle escape from the Sun. The radio module automatically detects type-III radio bursts from STEREO-A SWAVES real-time radio spectrograms and determines a set of parameters that narrow down detected type-III radio bursts to those that have the potential of causing near-Earth significant solar proton events. HESPERIA REleASE+ issues a proton alert only if the relativistic electron module creates an alert within the forecasting window set by the radio module. HESPERIA REleASE+ switches back to HESPERIA REleASE when data gaps in real-time radio data prevent proper identification of relevant type-III bursts.

The model uses real-time electron flux measurements from ACE/EPAM and SOHO/EPHIN, and real-time radio measurements from STEREO-A/SWAVES.

The HESPERIA REleASE+ model produces two forecasts: one based on inputs from SOHO/EPHIN and one based on ACE/EPAM electron data for two proton energy channels 15.8–39.8 MeV and 28.2–50.1 MeV. Forecasts are produced with a lead time of 30, 60, and 90 minutes. Based on these forecasts, the HESPERIA REleASE+ Alert module generates two alerts. One alert is based on the three most recent forecasts derived from SOHO/EPHIN data, and the other alert is based on the three most recent forecasts derived from ACE/EPAM data. HESPERIA REleASE+ forecasts and alerts are issued only when electron data predicts proton increases during the forecasting window set by the radio module. If no real-time radio data are available, the system reverts to HESPERIA REleASE forecasts and alerts.

Version 1.0 was deployed on the CCMC CR system on February 4, 2026.

The following sentences and acknowledgements shall appear inline where the HESPERIA REleASE tool is presented and also when the HESPERIA REleASE tool is cited, mentioned as well as when the relevant results are presented, cited and mentioned:

"HESPERIA REleASE+ has been developed through funding from the National Aeronautics and Space Administration under grant agreement No. TXS0150641A (National Observatory of Athens) and No. TXS0150642 (Christian-Albrechts-Universität) and has been built in the open-source programming language PYTHON"

Moreover, the logo of the HESPERIA project as well as the logo of the National Aeronautics and Space Administration (NASA) will be displayed in due prominence in all these occasions in proper image file format to be provided by NOA.

Any commercial use of the HESPERIA REleASE SEP forecasting results by NASA/CCMC and/or migration of the HESPERIA REleASE model to an external system, i.e., other than NASA/CCMC, will be possible only after signature of a separate agreement between NASA/CCMC, the National Observatory of Athens and the Christian-Albrechts Universitaet zu Kiel, Germany.