November 2004 Storms – Australian experiences

1. November 2004 Storms – Australian experiences By Phil Wilkinson, Garth Patterson and Patrick Phelan IPS Radio and Space Services Dept Industry, Tourism and Resources P O Box 1386, Haymarket NSW 1240 AUSTRALIA

2. November 2004 Storm - Solar • Forecasts • HF warnings for fadeouts were current • Region development meant there was always a potential for a major flare. • Alerts • Proton alert issued 7 Nov, and the PCA continued until 13 Nov. • Effects • M class flares Nov 3, 6 (with partial halo CME);X2 class flares Nov 7 (full halo, Type II/IV), 10 (Type II/IV). • Fadeouts occurred, but were not severe • PCA prevented HF equipment working in Antarctica • HF absorption observed at Hobart late afternoon 8th November • Coincident with northern hemisphere auroral sightings

3. November 2004 Storm – Mag-1 • Forecasts • Geomagnetic warnings current for period. • Initial (Nov 8) severity of storm not anticipated, • Ap = 60 expected, Ap = 189 observed. • Forecast based on M class flares Nov 5/6, plus weak halo CME • Was this the source of the disturbance on Nov 8? • Subsequent (Nov 10) storm expected, but severity under-estimated • X2 on 7th Nov expected to contribute further activity • Was this the source of renewed activity 10-11 Nov • and mid-latitude aurora? • and later development (Nov 11-12) over-estimated, • X2/3B flare considered a potential risk for increased activity • Parallel ribbon flare; Castell U, 3B for both Learmonth and Culgoora, all suggested this cold produce a major geophysical event, BUT IT DIDN’T. • Was the SI on 11th related to this event? The associated Bz > 0. • Alerts • Several auroral alerts issued (7 – 11 Nov, 2004), some to low latitudes (10 Nov). • Geomagnetic sudden impulses (SI) (Nov 7, 1 SI & Nov 9, 2 SI. Nov 11 1 SI) detected and alerts issued automatically.

4. November 2004 Storm – Mag-2 • Effects • Large positive and negative bays observed across Australia • At low latitudes these caused significant currents to flow in gas pipelines (being investigated). • Saturated IPS PC variometer array • Auroral sightings (23 email messages) across much of southern Australia, Europe (1) and northern USA • Nov 7, 09 – 11 UT, Sidings Springs and Western Australia, Europe, USA. • Nov 10, 08 – 1230 UT, Bathurst, Dunedin, Hobart. • Several pictures were provided • A collection of southern aurora pictures can be found at http://homepage.mac.com/stevoss/Menu8.html

5. November 2004 Storm – Mag - 3

6. November 2004 Storm – Mag - 4 • Aurora – Siding Springs Observatory, NSW, 8th November (0950 - 1030 UT) • Credit: Gordon Garradd (http://members.ozemail.com.au/~loomberah)

7. November 2004 Storm – Mag - 5 • Aurora – Bathurst, NSW – observed for 10 minutes, 10th November (1047 – 1057 UT) • Credit: Ray Pickard, Bathurst Observatory (http://www.bathurstobservatory.com.au)

8. November 2004 Storm – Solar wind-1 • Alerts • Solar wind shocks and geomagnetic Sudden Impulses are automatically detected and alerts issued. • Solar wind shocks (7 Nov, 3 shocks; Nov 9, 2 shocks), • and geomagnetic sudden impulses (SI) (Nov 7, 1 SI & Nov 9, 2 SI. Nov 11 1 SI). • All events detected automatically and alerts issued.

9. November 2004 Storm – Solar wind-2 • Solar wind Interplanetary Field: November 3 – 14, 2004 • Source: SEC (composite image) http://www.sec.noaa.gov/Data/solar.html

10. November 2004 Storm – Solar wind-3 • Solar wind particle fluxes: November 3 – 14, 2004 • Source: SEC (composite image) http://www.sec.noaa.gov/Data/solar.html

11. November 2004 Storm – Ionosphere - 1 • Forecasts • HF warnings current for storm period, • Duration of storm not correct • Allowing for possible increased activity • Effects • Maximum Useable Frequencies (MUF) depressed 7 Nov. • Due to large height rises rather than depressed peak densities. • Greater ionospheric variability • Than usually experienced during large storms • Large ionisation gradients across Australia • Hemispheric differences • Southern (summer) hemisphere affected more than northern (winter) hemisphere (note indices).

12. November 2004 Storm – Ionosphere - 2

13. November 2004 Storm – Ionosphere - 3

14. November 2004 Storm – Ionosphere - 4

15. November 2004 Storm – Media - 1 • Press release • Prepared for release Nov 8, released Nov 9 • Delay unavoidable, but ultimately useful • Considerable interest, especially the prospect of observing aurora • Press • Coverage in local newspapers, including auroral pictures from event • Also on some media websites • Radio • Featured on prime news bulletins and drive time • TV • One TV interview used.

16. November 2004 Storm – Media - 2 • Aurora – observed Thursday 11th November, near Hobart • Credit: Hobart mercury, November 11th or 12th, 2004

17. November 2004 Storm – Timeline

18. November 2004 Storm – Summary • Forecasts: • Warnings for fadeouts and geomagnetic activity were current for the storm period • Severity of storm was not correctly forecast • Duration of geomagnetic and ionospheric storm not correctly forecast • Partly because a third storm, predicted for 11th November, did not eventuate. • Alerts: • Auroral alerts for the period were reasonably helpful for observers (see timeline) • Effects: • Australasian ionosphere severely disturbed • Major gradients and significantly increased spatial variability • Severe geomagnetic disturbances observed • Caused extreme current flows in low latitude gas pipeline • Aurora • Wide observations of active displays • Media • Good media interest, especially in the potential for auroral observations