Solar Terrestrial Activity Report

Last update issued on January 20, 2003 at 04:30 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 13, 2003)]

Recent activity

The geomagnetic field was quiet to active on January 19. Solar wind speed ranged between 447 and 716 km/sec under the influence of a strong coronal stream.

Solar flux measured at 20h UTC on 2.8 GHz was 130.2. The planetary A index was 16 (STAR Ap - based on the mean of three hour interval ap indices: 16.4).
Three hour interval K indices: 22344433 (planetary), 22344433 (Boulder).

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

At midnight there were 12 spotted regions on the visible disk, 2 of which has not yet been numbered by SEC/NOAA. Solar flare activity was very low. No C class flares were recorded.

Region 10250 decayed slowly and lost the spots which had emerged the previous day.
Region 10251 decayed slowly and quietly and is rotating over the southwest limb.
Region 10254 decayed and lost all trailing spots.

Region 10255 was split off from region 10251 on January 12 by SEC/NOAA. This split was doubtful even then and it is currently obvious that it was a premature decision.
Region 10256 was split off from region 10254 on January 12 by SEC/NOAA. Regions 10254 and 10256 make up one bipolar region with the negative polarity area in the west and the positive area to the east.

Region 10257 developed slowly and quietly.
Region 10258 was quiet and stable.
Region 10259 decayed slowly and quietly.
Region 10260 developed moderately quickly and was quiet.
New region 10261 emerged on Jan.18 in the northwest quadrant and was numbered the next day.
New region 10262 emerged on Jan.18 in the southwest quadrant and was numbered the next day.
New region 10263 emerged near the central meridian and rotated into the southwest quadrant.

Spotted regions not numbered by SEC/NOAA:
[S77] A new region emerged in the southeast quadrant. Location at midnight: S19E08.
[S78] A new region emerged near the southeast limb. Location at midnight: S24E70.

Coronal mass ejections (CMEs)

January 17-19: 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 huge trans equatorial extension of the southern polar coronal hole will be in a geoeffective position on January 16-23.

Processed SOHO EIT 284 image at 01:06 UTC on January 20. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be unsettled to minor storm until January 26 due to a coronal stream. 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 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.