Operational Forecasting Capability Today and Tomorrow Radiation Storms

1. Operational Forecasting CapabilityToday and TomorrowRadiation Storms Ron Zwickl with material from Joseph Kunches, Christopher Balch, and William Murtagh NOAA Space Environment Center Boulder, Colorado and Janet Luhmann et. al. CISM Model Oct. 17, 2005

3. Today:NOAA SEC’s Operational Prediction Model • Model based on empirical & statistical relationships • Practical aspects of this kind of model: • Must be based on specific observations of a solar event • The observations must be routinely available in real-time • Assessment must be done in real-time – prior to arrival of the first particles (particles may arrive before solar event is over) • RT analysis sometimes requires estimates of the input parameters • Forecasters may consider other factors in making a decision to issue a warning or a forecast.

4. Solar Cycle 23 produced 31 >100 MeV radiation storms. The Large Events (in pfu’s) 14 Jul 2000 410 28 Oct 2003 186 8 Nov 2000 347 29 Oct 2003 110 15 Apr 2001 146 20 Jan 2005 652 4 Nov 2001 253 180 160 140 120 100 80 60 40 20 0 2003 2000 1976 1988 1997 1979 1982 1985 1991 1994 Cycle 23 Radiation Storms 80 - The Sep 2005 radiation storm was the 91st >10 MeV radiation storm of Solar Cycle 23. Totals = S3 (10) S4 (6) S5 (0) 70 - 60 - 50 - 40 - 30 - 20 - 10 - Radiation Storms per Cycle

5. SEP event occurrence varies with the solar cycle in antiphase with galactic cosmic ray fluxes R. Mewaldt

6. Solar Flare Activity 1976-2004 Courtesy R. Fisher, NASA

7. NOAA SEC nowcasts, forecasts, products • GOES real-time particle flux data • Range of energies 0.6 – 500 MeV • Event defined as flux of 10 p cm-2 s-1 ster-1 (PFU) at > 10 MeV • Daily forecast • Three day probabilities for SEP events • Short term warnings • Based primarily on flare observations • Thresholds: 10 PFU  10 MeV and 1 PFU  100 MeV • Prediction for onset time, maximum flux, time of maximum flux, and expected event duration • Alerts • Real-time reports of an observed event • Issued shortly after threshold has been attained • Additional notices at 100, 1000, and 10000 PFU. • Event Summaries • Important for users to have an ‘all-clear’ indicator

8. Input parameters • GOES XRS data: • X-ray event peak flux • Time of maximum • Integrated x-ray flux (over time) • Ground-based H-alpha patrol or GOES-12 SXI • Location of the solar activity on the disk • Radio Telescope patrol (USAF SEON) • Reports of type II radio sweep • Reports of type IV radio sweep

9. Probability Calculation • Based on integrated x-ray flux, peak x-ray flux, and occurrence of type II and type IV radio sweeps • Current model was developed in 1998 and uses historical statistics • Example: Integrated flux [0.085-0.257] X-ray class  [M3-M8] Radio sweep type II and type IV: 16 such events historically, 6 of which were associated with proton events => 37.5 % probability (±12%)

10. Peak Flux Calculation • Based on a best fit line of historical data between the log of integrated x-ray flux and the log of peak proton flux • Result below based on 1998 analysis

11. Uses the same form for input parameter space Update the probability prediction based on statistics of 1996-2003 data Any bins with less than 10 events are not used In this case, events are combined and fewer parameters are used Reliability diagram using 1996-2003 data

12. Rise Time Calculation • Based on a best fit of historical data: time from flare maximum to proton event maximum as a function of source longitude: • tmin = 9.4 • longitude = 78.0 •  = 18.1

13. Rise time relationship: 1998 analysis

14. Additional parameters under study • Derived temperature from GOES XRS (Garcia 1994) • Low temperature flares have a higher degree of association with SEPs than high temperature flares

15. Summary • Today’s space weather warnings for SEP’s are based on an empirical-statistical model • The main outputs: • Probability for an SEP event • Peak flux at 10 MeV • Rise time (between flare max and SEP max)

16. Gradual SEP Event with an ESP (energetic storm particle) Event: some SEP events have two peaks- a prompt one arriving 10s of minutes after the solar activity, and a second, arriving with the ICME shock

17. Multipoint measurements show that SEP event energy spectra depend on both time and location. A good global model should reproduce this.

18. MARIE and GOES DataApril 2002 50 Dose Rate (mrads/day) S14E150 30 10 104 GOES 8 103 X1 Flare W limb CME S14W84 102 April 30, 2002 (128 degrees) Particles/cm2 sec sr 101 Earth 1.0 Sun 10-1 Mars 1 6 11 16 21 26 31 Courtesy F. Cucinotta, NASA

19. MARIE and GOES DataOctober 2002 October 1, 2002 (153 degrees) 104 Sun Earth Mars 103 Dose Rate (mrads/day) 102 October 15, 2002 (146 degrees) 101 Sun Earth Mars 102 GOES 8 101 October 31, 2002 (137 degrees) Particles/cm2 sec sr 1.0 Sun 10-1 Mars Earth 1 6 11 16 21 26 31 Courtesy F. Cucinotta, NASA

20. Conditions for both the SEP Shock Source and Transport can be derived from the CISM models Shock Front Surface Magnetic Field Lines theta = 60 deg theta = 70 deg theta = 80 deg theta = 90 deg • Magnetic field lines, as observed at given locations can be: • part of the magnetic flux rope; • connected to the solar surface; or • disconnected from the solar surface. (Images: D. Odstrcil)

21. CISM MAS/ENLIL models have all the details of both the coronal field structure And the CME/ICME transient Detail of an ad-hoc simulated CME in the model solar wind Ambient Solar Wind ICME Shock and Sheath ICME Flux Rope Field Lines Image courtesy of Dusan Odstrcil, CIRES

22. The cone model produced a detailed picture of the evolution of the disturbance in the solar wind out to 1 AU, including all of the information needed for the SEP calculations

23. Future Studies will use MHD simulation results including the CME/ICME ejecta Based on adhoc 3D coronal eruption generated from a sheared field arcade with photospheric flux cancellation From J. Linker Resulting in a 3D Magnetic Flux Rope - Expanding into coupled solar wind model. From D. Odstrcil

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