Solar Terrestrial Activity Report

Last update December 6, 2002 at 03:40 UTC.

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

Recent activity

The geomagnetic field was quiet to unsettled on December 5. Solar wind speed ranged between 379 and 448 km/sec.

Solar flare activity was low. Solar flux was 148.7, the planetary A index was 9 (STAR Ap - based on the mean of three hour ap indices: 10.6).
Three hour interval K indices: 33232322 (planetary), 32232211 (Boulder).

The background x-ray flux is at the class B3-4 level.

At midnight there were 7 spotted regions on the visible disk. Only 2 low level C flares were recorded during the day, including an optically uncorrelated C1.0 event at 22:06 UTC.

Region 10205 decayed and was spotless by early evening.
Region 10207 decayed slowly and quietly.
Region 10208 decayed slowly losing penumbral area in the leading spot section. Flare: C1.1 at 04:50 UTC. 
Region 10209 lost all trailing spots, the leading penumbra was unchanged.
Region 10212 developed slowly and was quiet.
Region 10213 decayed with the main penumbra losing about half of its area.
New region 10214 emerged in the northwest quadrant on Dec.4 and developed moderately quickly on Dec.5.
New region 10215 rotated into view at the southeast limb. There could be another region trailing this one as the southeast limb is quite bright in SOHO EIT images.

Coronal mass ejections (CMEs)

December 3-5: No obviously geoeffective CMEs noted.

Coronal holes

Coronal hole history (starting late October 2002)
Compare today's report with the situation one solar rotation ago: -1 day 27 days ago +1 day

The southernmost part of an extension of the northern polar coronal hole may have been in a geoeffective position on December 4. A slowly developing trans equatorial coronal hole was in a geoeffective position on December 4.

Processed SOHO EIT 284 image at 19:06 UTC on December 5. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on December 6 and quiet to active on December 7-8. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair.

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)

Composite image based on a SOHO/MDI continuum image and overlaid by a coronal hole image. Region numbering has been included.

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.