Solar Terrestrial Activity Report

Last update January 9, 2003 at 04:00 UTC.

[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update January 1, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 1, 2003)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update January 1, 2003)]
[Historical solar and geomagnetic data charts 1954-2002 (last update October 13, 2002)]
[Archived reports (last update January 6, 2003)]

Recent activity

The geomagnetic field was quiet to unsettled on January 8. Solar wind speed ranged between 275 and 321 km/sec. 

Solar flux measured at 20h UTC on 2.8 GHz was 173.7. The planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 8.5).
Three hour interval K indices: 22322222 (planetary), 21312211 (Boulder).

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

At midnight there were 8 spotted regions on the visible disk. Solar flare activity was low. A total of 14 C class events were recorded during the day.

Region 10242 decayed further in the northern spot sections losing a significant amount of penumbral area. Some development was observed in the southern spot section during the first half of the day. The region could produce an M class flare. Flares: C2.0 at 02:38, C3.4 at 07:31, C2.6 at 08:47, C1.7 at 09:21, C2.5 at 15:30 and C1.7 at 16:27 UTC. /A C9.8 long duration event peaking at 01:35 UTC was observed on Jan.9/
Region 10244 decayed and lost about half of its penumbral area. Flare: C6.2/1F at 05:52 UTC.
Region 10245 decayed early in the day, then began to develop slowly. Early on Jan.9 mixed polarities are evident.
Region 10247 developed very quickly during the latter half of the day and will soon become the largest region on the visible disk. A huge amount of positive magnetic flux emerged and there is currently a magnetic delta structure in the largest northern penumbra. M class flares are certainly possible and, if the region continues to develop at its current rate, an X class flare could soon become possible. Flare: C1.5 at 23:23 UTC.
Region 10248 decayed and could soon become spotless.
Region 10249 developed slowly and quietly.
Region 10250 developed slowly and may be capable of producing a minor M class flare.. Flares: C3.0 at 07:22 and C1.8 at 21:42 UTC.
Region 10251 rotated fully into view revealing a magnetic delta structure in the trailing spot section. M class flares are possible, though it should be noted that slow decay was observed late in the day in spots outside of the two main penumbrae. Flare: C1.4 at 01:35 UTC.

Coronal mass ejections (CMEs)

January 6-8: No obviously geoeffective CMEs observed.

Coronal holes

Coronal hole history (since late October 2002)
Compare today's report with the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A recurrent trans equatorial extension of the northern polar coronal hole was in a geoeffective position on January 6.

Processed SOHO EIT 284 image at 01:06 UTC on January 9. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to active on January 9-10 with quiet to unsettled likely for January 11-12. 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. Compare to the previous day's image.

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 inside a few hours before 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. All time references are to the UTC day. Comments and suggestions are always welcome.