Solar Terrestrial Activity Report

Last update issued on January 30, 2003 at 03:30 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 January 27, 2003)]
[Archived reports (last update January 27, 2003)]

Recent activity

The geomagnetic field was quiet to active on January 29. Solar wind speed ranged between 389 and 468 km/sec. A coronal stream began to dominate the solar wind as early as 08h UTC.

Solar flux measured at 20h UTC on 2.8 GHz was 124.4. The planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.8).
Three hour interval K indices: 22233444 (planetary), 21233423 (Boulder).

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

At midnight there were 7 spotted regions on the visible disk. Solar flare activity was low. A total of 2 C class events was recorded.

Region 10266 decayed substantially and lost all spots outside of the main penumbra as well as about half of its penumbral area. Flare: C1.1 at 20:33 UTC
Region 10269 was mostly unchanged and quiet.
Region 10271 was mostly unchanged, the leading penumbra increased its areal coverage.
Region 10272 developed slowly early in the day, then began to decay.
Region 10273 decayed in the trailing spot section while some development was observed in the leading spots. Flare: C1.1 at 13:10 UTC
Region 10274 was quiet and stable.
New region 10275 emerged southeast of region 10272 on January 28 and was numbered the next day. The region decayed slowly during the latter half of the day and could soon become spotless.

Coronal mass ejections (CMEs)

January 28-29: 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. Two coronal hole in the northern hemisphere will be geoeffective on January 29-30. A trans equatorial coronal hole will rotate into a geoeffective position on February 2 or 3.

Processed SOHO EIT 284 image at 01:06 UTC on January 30. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be unsettled to minor storm on January 30 and quiet to active on January 31 due to a coronal stream. Another coronal stream will likely arrive on February 1 and cause mainly unsettled conditions until February 2. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor, propagation along north-south paths 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.