Solar Terrestrial Activity Report

Last update issued on January 29, 2003 at 03:15 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 January 27, 2003)]
[Archived reports (last update January 27, 2003)]

Recent activity

The geomagnetic field was quiet to active on January 28. Solar wind speed ranged between 413 and 493 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 125.6. The planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 13.0).
Three hour interval K indices: 33432322 (planetary), 33432222 (Boulder).

The background x-ray flux is at the class B2 level.

At midnight there were 10 spotted regions on the visible disk, 1 of which has not yet been numbered by SEC/NOAA. Solar flare activity was low. Only 1 C class event was recorded.

Region 10266 decayed slowly and was mostly quiet. Flare: C3.2 flare at 23:50 UTC
Region 10267 decayed slowly and will soon become spotless if the current rate of decay persists.
Region 10268 decayed slowly and quietly.
Region 10269 decayed slowly and quietly.
Region 10270 decayed and lost its trailing spot.
Region 10271 developed slowly adding several spots.
Region 10272 developed quickly as new flux emerged. Some polarity intermixing is currently evident.
Region 10273 developed further becoming the largest region on the visible disk. Further development will increase the chances of a minor M class flare.
New region 10274 rotated into view at the southeast limb on January 27 and was numbered the next day.

Spotted regions not yet numbered by SEC/NOAA:
[S83] A new region emerged in the southeast quadrant. Location at midnight: S10E06.

Coronal mass ejections (CMEs)

January 26 and 28: No obviously geoeffective CMEs observed.

January 27: A filament eruption in the southwest quadrant (between regions 10266, 10267 and 10271) during the evening was associated with a partial halo CME off the south pole and the southwest and southeast limbs. There is a minor possibility that the CME could have geoeffective extensions.

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 small trans equatorial coronal hole was in a geoeffective position on January 26-27. A coronal hole in the northern hemisphere will become geoeffective on January 30. A small trans equatorial coronal hole will probably rotate into a geoeffective position on February 2 or 3.

Processed SOHO EIT 284 image at 01:06 UTC on January 29. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled most of January 29. Quiet to active is likely from late on January 29 until January 31 due to a coronal stream. 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)

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.