Solar Terrestrial Activity Report

Last update November 12, 2002 at 03:40 UTC. Due to internet access problems early on November 13, the next update will be posted at approximately 11 UTC on Nov.13

[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update November 2, 2002)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 2, 2002)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update November 2, 2002)]
[Historical solar and geomagnetic data charts 1954-2002 (last update October 13, 2002)]
[Archived reports (last update November 9, 2002)]

Recent activity

The geomagnetic field was quiet to active on November 11. Solar wind speed ranged between 388 and 703 km/sec. A coronal stream was in progress all day. However, one or two solar wind shocks could be detected in ACE data. The first was exactly at noon when solar wind speed increased to near 600 km/sec accompanied by a brief increase in solar wind density. The second, and most obvious candidate for a solar wind shock was at 13:53 UTC when solar wind speed increased abruptly from 610 to nearly 700 km/sec. ACE EPAM data confirms that a solar wind shock passed by the spacecraft at that time. This shock was caused by the arrival of the halo CME observed on November 9 following an M4 event in region 10180. The presence of a coronal stream at the time when this CME arrived had surprising effects on the interplanetary magnetic field. The IMF weakened a lot and was northwards for the remainder of the day.

Solar flare activity was moderate. Solar flux was 184.7, the planetary A index was 12 (STAR Ap - based on the mean of three hour ap indices: 12.9).
Three hour interval K indices: 22334323 (planetary), 22333222 (Boulder).

The background x-ray flux is at the class C1 level.

At midnight there were 6 spotted regions on the visible disk. A total of 11 C and 3 M class events were recorded during the day. Old region 10175 behind the northwest limb produced a C4.9 flare at 01:23 UTC.

Region 10177 rotated out of view at the northwest limb.
Region 10180 decayed quickly losing many spots and about half of its penumbral area. Further M class flaring is possible until the region rotates out of view on Nov.13. Flares: C2.9 long duration event peaking at 06:10, M2.9/1N long duration event peaking at 07:33, C7.1/1F long duration event peaking at 12:54, C5.0 at 13:41, C6.5 at 14:45, M1.5 at 15:24, M1.8/1N long duration event peaking at 16:20 and C2.2 at 21:02 UTC.
Region 10182 was quiet and stable.
Region 10185 decayed further and was quiet.
Region 10188 decayed and was spotless by the end of the day. Flare: C2.4 long duration event peaking at 04:38 UTC.
Region 10189 decayed and was spotless before noon.
Region 10190 was quiet and stable
Region 10191 developed further and spread out over a large area. No magnetic delta structures were visible by noon. A major flare is possible. Flare: C7.4 long duration event peaking at 22:56 UTC.
New region 10192 emerged in the northeast quadrant near midnight, developed quickly early on, then began to decay.

Coronal mass ejections (CMEs)

November 10: A partial halo CME with the main part of the ejection off the southwest limb was observed after the M2 event in region 10180 early in the day. This CME could reach Earth on November 12. A CME was observed off the east limb during the morning following a long duration C5 event in region 10191.

November 11: A large filament eruption in the southern hemisphere began near 11h UTC and produced a partial halo CME. The CME is probably not geoeffective. A long duration M1 event in region 10180 after 16h UTC was associated with a CME off the southwest limb. A long duration C7 event in region 10191 was likely associated with a CME off of the southeast limb late in the day.

Coronal holes

A trans equatorial coronal hole will be in a geoeffective position on November 12-13.

Enhanced SOHO EIT 284 image at 01:06 UTC on November 12. The black areas on the solar disk  are coronal holes.

Forecast

The geomagnetic field is expected to be quiet to active on November 12-13 and the first half of November 14. During the latter half of November 14 a strong coronal stream is likely to arrive and could cause unsettled to major storm conditions early on, becoming unsettled to minor storm by the latter half of November 15. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor.

Coronal holes (1)	Coronal mass ejections (2)	M and X class flares (3)

1) Effects from a coronal hole could reach Earth within the next 5 days.
2) Material from a CME is likely to impact Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 hours.

Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.

Active solar regions (Recent map)

The above image is a test composite image displaying the currently spotted regions overlaid by a coronal hole image. The basis for the region image is a SOHO/MDI image late on November 11. Region numbering and other image processing has been applied by myself. 

Data for all numbered solar regions according to the Solar Region Summary provided by SEC/NOAA. Comments are my own, as is the STAR spot count (spots observed at or just prior to midnight) and data for regions not numbered by SEC or where SEC has observed no spots.

Monthly solar cycle data

1) Running average based on the daily 20:00 UT observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% less.

This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. Comments and suggestions are always welcome.