Last major update issued on December 5, 2003 at 04:15 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 unsettled on December 4. Solar wind speed ranged between 327 and 379 km/sec. Solar wind speed and the total field of the interplanetary magnetic field increased slowly after 12h UTC as a fairly low speed stream from coronal hole CH70 began to dominate the solar wind. This coronal hole related stream increased in intensity after 02h UTC on December 5 with the IMF swinging strongly southwards.
Solar flux measured at 20h UTC on 2.8 GHz was 115.8. The planetary A
index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 10.0).
Three hour interval K indices: 21233333 (planetary), 11121223 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 6 spotted regions on the visible disk. Solar flare activity was low. A single C class event was recorded during the day.
Region 10510 developed early in the day, then began to decay. Flare:
C2.2 at 01:22 UTC.
Region 10513 was quiet and stable.
Region 10516 was quiet and stable.
Region 10517 developed slowly and was quiet.
Region 10518 was quiet and stable, the region could soon become spotless.
New region 10519 emerged in the southeast quadrant on December 3 and was numbered the next day by SEC. The region developed slowly early on December 4 while slow decay was observed late in the day.
December 3-4: No partly or fully earth directed CMEs observed.
December 2: A full halo CME was observed in LASCO C3 images beginning at 11:18 UTC. This CME was large and very wide. While expansion was fast off of the west limb, the CME was faint and slow over the east limb. A flank CME impact is possible on December 5 or 6.
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 recurrent trans equatorial coronal hole (CH70) was in a geoeffective position on December 1 - December 2. CH70 appeared to be decaying on December 3-4. A huge recurrent trans equatorial coronal hole (CH71) will be in a geoeffective position on December 4-12 with the associated high speed stream influencing the geomagnetic field from December 7.
Processed SOHO/EIT 284 image at 01:06 UTC on December 5. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to major storm on December 5 due to effects from coronal hole CH70 and quiet to active on December 6. A weak CME impact is possible on December 5 or 6. A strong high speed stream from coronal hole CH71 should dominate the solar wind from December 7 until approximately December 15.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along long distance north-south paths is fair to good. [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 0030
classification was CAO
formerly region S319
area was 0030
|Total spot count:||35||40|
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||130.6 (1)||15.9 (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.