Solar Terrestrial Activity Report

Last update December 29, 2002 at 01:50 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 23, 2002)]

Recent activity

The geomagnetic field was quiet to active on December 28. Solar wind speed ranged between 603 and 778 km/sec under the influence of a strong coronal stream.

Solar flare activity was low. Solar flux was 116.9, the planetary A index was 19 (STAR Ap - based on the mean of three hour ap indices: 19.3).
Three hour interval K indices: 44443432 (planetary), 34443322 (Boulder).

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

At midnight there were 3 spotted regions on the visible disk, 1 of which has not yet been numbered. The only C class event noted during the day was an optically uncorrelated C1.4 flare at 23:14 UTC.

Region 10234 was quiet and stable.
Region 10236 decayed slightly and was quiet.

Spotted regions not yet numbered by SEC:
[S62] A new region emerged in the southeast quadrant early in the day. Location at midnight: S09E51.

Coronal mass ejections (CMEs)

December 26-28: No obviously geoeffective CMEs observed. A moderately large CME was observed off of the northwest limb late on Dec.28 but did not appear to have any geoeffective components.

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 fairly small, recurrent, trans equatorial coronal hole will likely rotate into a geoeffective position on January 1.

Processed SOHO EIT 284 image at 19:06 UTC on December 28. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to active on December 29 due to a coronal stream and quiet to unsettled on December 30-31. 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)

Composite image based on a [Temporarily replaced: SOHO/MDI continuum image] processed BBSO white light image and overlaid by a coronal hole image. Region numbering has been included. Compare to the previous day's image. Yesterday's SOHO/MDI (SOI) processed continuum image at 22:24 UTC - image includes region numbering.

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. Comments and suggestions are always welcome.