# Presentation: 919582

## Operational Forecasting CapabilityToday and TomorrowRadiation 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

## Slide 2

## 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.**

## Cycle 23 Radiation Storms 

***Cycle 23 Radiation Storms****** ***

**80  **

**-**

**70  **

**-**

**60  **

**-**

**50  **

**-**

**40  **

**-**

**30  **

**-**

**20  **

**-**

**10  **

**-**

**Radiation Storms**

**per Cycle**

- The Sep 2005 radiation storm was the 91st >10 MeV radiation storm of Solar Cycle 23.
-        ***Totals = S3 ******(10)******   S4 ******(6)******    S5 ******(0)****** ***

## SEP event occurrence varies with the solar cycle in antiphase with galactic cosmic ray fluxes

- _R. Mewaldt_

## Solar Flare Activity 1976-2004

- Courtesy R. Fisher, NASA

## 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

## 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

## 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%)

## 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

## Reliability diagram using 1996-2003 data

- 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

## 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

## Rise time relationship: 1998 analysis

## 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

## 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)

## 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

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

## MARIE and GOES DataApril 2002

- MARIE and GOES DataApril 2002

**10****3**

**10****1**

**1.0**

**10****-1**

**Particles/cm****2**** sec sr**

**10****2**

**Dose Rate (mrads/day)**

**10**

**50**

**30**

**1**

**6**

**11**

**16**

**21**

**26**

**31**

**10****4**

**GOES 8**

**Sun**

**Mars**

**Earth**

**April 30,  2002**

**(128 degrees)**

- Courtesy F. Cucinotta, NASA

- S14E150

- X1 Flare
- W limb CME
- S14W84

## MARIE and GOES DataOctober 2002

**10****1**

**1.0**

**10****-1**

**Particles/cm****2**** sec sr**

**10****2**

**Dose Rate (mrads/day)**

**1**

**6**

**11**

**16**

**21**

**26**

**31**

**GOES 8**

**10****1**

**10****2**

**10****3**

**10****4**

**Sun**

**Mars**

**Earth**

**October 15,  2002**

**(146 degrees)**

**Sun**

**Mars**

**Earth**

**October 1,  2002**

**(153 degrees)**

**Sun**

**Mars**

**Earth**

**October 31,  2002**

**(137 degrees)**

- Courtesy F. Cucinotta, NASA

- MARIE and GOES DataOctober 2002

## Conditions for both the SEP Shock Source and Transport can be derived from  the CISM models

**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.**

**Shock Front Surface**

**Magnetic Field Lines**

**theta = 90 deg**

**theta = 60 deg**

**theta = 70 deg**

**theta = 80 deg**

**Conditions for both the SEP Shock Source and Transport can be derived from  the CISM models**

- _(Images: D. Odstrcil)_

## Detail of an ad-hoc simulated CME in the model solar wind

*Image courtesy of Dusan Odstrcil, CIRES*

**ICME Flux Rope Field Lines**

**ICME Shock and Sheath**

**Ambient Solar Wind**

**Detail of an ad-hoc simulated CME in the model solar wind**

**CISM MAS/ENLIL models have all the details of both the coronal field structure**
**And the CME/ICME transient**

## 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

## Future Studies will use MHD simulation results including the CME/ICME ejecta                       

*From J. Linker*

**Resulting in a 3D Magnetic Flux Rope - Expanding into coupled solar wind model.                              ***From D. Odstrcil*

**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**

## End