Last major update issued on December 8, 2003 at 03:45 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update December 2, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update December 2, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update December 2, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update October 15, 2003)]
[Archived reports (last update December 1, 2003)]
The geomagnetic field was quiet to active on December 7. Solar wind speed ranged between 352 and 507 km/sec. A weak solar wind shock was observed at SOHO at 14:01 UTC. Solar wind speed increased abruptly from 381 to 447 km/sec. Otherwise solar wind speed increased generally slowly all day. Early on December 8 wind speed increased further and it appears as if the high speed stream from coronal hole CH71 is arriving.
Solar flux measured at 20h UTC on 2.8 GHz was 92.0. The planetary A
index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 16.3).
Three hour interval K indices: 22333443 (planetary), 22433443 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 3 spotted regions on the visible disk. Solar flare activity was low. A total of 4 C class events were recorded during the day, all from region 10510 behind the southwest limb: C2.3 long duration event peaking at 00:53, C1.3 at 02:20, C3.1 at 02:54 and C1.1 at 06:27 UTC.
Region 10513 was quiet and stable and will soon rotate over the northwest limb.
Region 10516 decayed further and lost the trailing spots.
Region 10517 decayed and lost most of the small spots as well as most of the penumbra in the trailing spot section.
December 6: Only a few LASCO images from early in the day are available as I write this. A CME can be observed off of the southwest limb and may be associated with the southwest quadrant erupting filament seen in EIT images. This CME may be partly earth directed.
December 5 and 7: No partly or fully earth directed CMEs observed.
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 recurrent trans equatorial coronal hole (CH71) will be in a geoeffective position on December 5-12.
Processed SOHO/EIT 284 image at 01:06 UTC on December 8. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet early on December 8, then unsettled to minor storm with occasional major and severe storm intervals until December 15 due to a strong high speed stream from coronal hole CH71.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor to useless. Propagation along long distance north-south paths is fair to poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Rafaela (Argentina)].
|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. When the high speed stream has arrived
the color changes to green.
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.
Compare to the previous day's image.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SEC. 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. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.
|Active region||Date numbered||SEC
|Location at midnight||Area||Classification||Comment|
area was 0040
classification was CSO
at midnight, area 0050
classification was DSO
at midnight, area 0120
|Total spot count:||23||8|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.06||129.3||77.4||(65.3 predicted, -2.5)|
|2003.07||127.7||85.0||(61.9 predicted, -3.4)|
|2003.08||122.1||72.7||(59.0 predicted, -2.9)|
|2003.09||112.2||48.8||(57.0 predicted, -2.0)|
|2003.10||151.7||65.6||(54.3 predicted, -2.7)|
|2003.11||140.8||67.2||(51.6 predicted, -2.7)|
|2003.12||119.3 (1)||23.3 (2)||(49.0 predicted, -2.6)|
1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (NOAA/SEC) sunspot number. The official international sunspot number is typically 30-50% less.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.