Solar Terrestrial Activity Report

Last update November 10, 2002 at 03:30 UTC. Minor update posted at 17:20 UTC.

[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 unsettled on November 9. Solar wind speed ranged between 348 and 410 km/sec. A solar wind shock was observed at ACE at 18:00 UTC with a sudden increase in solar wind speed from 360 to 400 km/sec. This shock probably had its origin in an unexpected CME but was unusual in that ACE EPAM parameters did not indicate the presence of a CME and that there was a gradual increase in solar wind density during the hours prior to the arrival of the shock.

Solar flare activity was moderate. Solar flux was 190.6, the planetary A index was 9 (STAR Ap - based on the mean of three hour ap indices: 10.0).
Three hour interval K indices: 22122333 (planetary), 11111133 (Boulder).

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

A proton event and an associated polar cap absorption event is in progress. The above 10 MeV proton flux has so far peaked near the 240 pfu level.

At midnight there were 9 spotted regions on the visible disk. A total of 14 C and 1 M class events were recorded during the day. A C4.7 flare at 09:54 UTC apparently had an origin just behind the northwest limb. Several flares have been observed early on Nov.10: C5.4 at 01:24, C5.5 at 01:33, C6.2 at 02:02, C7.7 at 02:14, C8.1 at 02:17 and a long duration M2.4 event peaking at 03:21 UTC. Activity has been observed in regions 10180 and 10191.

Region 10176 was quiet and stable.
Region 10177 decayed quietly with most of the decay occurring in the southern spot section.
Region 10180 decayed further in the trailing spot section and lost quite a few of the intermediate spots as well. A magnetic delta structure is still present in the leading penumbra as well as in the largest intermediate penumbra. There is still a chance of a major flare. Flares: C1.5 at 00:38, C2.8 long duration event peaking at 02:31, C1.6 at 04:26, C6.3 at 11:58, M4.6/2B (associated with moderate type II and IV sweeps and having its origin in the southeastern part of the region) proton flare at 13:23 and C4.1 at 15:26 UTC.
Region 10182 was quiet and stable.
Region 10185 developed slowly and quietly.
Region 10188 decayed moderately quickly and was mostly quiet.
Region 10189 was mostly unchanged and quiet.
Region 10190 was generally unchanged and quiet.
Region 10191 developed slowly and appears to have a magnetic delta structure in the easternmost penumbra. M class flares are possible. Flare: C7.9 at 17:52 UTC.

Comment added at 17:20 UTC on November 10: The M2 event early today in region 10180 was associated with a type II sweep and a fairly fast CME mainly off the southwest limb. Region 10180 has since decayed significantly and the most active areas have been behind the northwest limb and in region 10191. Region 10191 has developed quickly and is already much larger than region 10180. There is at least one magnetic delta structure in this region and a major flare is possible. The geomagnetic field has been quiet to minor storm. A coronal stream is beginning to dominate the solar wind and solar wind speed has been increasing slowly since 13h UTC.

Coronal mass ejections (CMEs)

November 7-8: No obviously geoeffective CMEs were observed.

November 9: A full halo CME was observed after the M4 event in region 10180. The CME was well defined over the southern hemisphere limbs and fairly weak over the north pole and the northern part of the northeast limb. The CME will likely impact Earth sometime between 18h UTC on November 11 and noon on November 12 and could cause unsettled to minor geomagnetic storm conditions.

Coronal holes

The southernmost extension of the northern polar coronal hole was in a geoeffective position on November 7. A trans equatorial coronal hole will likely be in a geoeffective position on November 12-13.

Enhanced SOHO EIT 284 image at 19:06 UTC on November 9. The black areas on the solar disk  are coronal holes.

Forecast

The geomagnetic field is expected to be unsettled to minor storm on November 10-12. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very 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 from late on November 9. 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.