Last major update issued on December 24, 2003 at 04:10 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 17, 2003)]
The geomagnetic field was quiet to unsettled on December 23. Solar wind speed ranged between 463 and 632 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 142.0. The planetary A
index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.6).
Three hour interval K indices: 22133332 (planetary), 11122321 (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 total of 7 C class events were recorded during the day.
Region 10523 was quiet and stable. The region could soon become spotless.
Region 10524 reemerged with a few small spots.
Region 10525 decayed in the leading and trailing spot sections. There is still a weak magnetic delta structure in a central penumbra. A minor M class flare is possible. Flares: C1.1 at 01:25, C1.6 at 07:32 and C6.9 at 10:24 UTC.
Region 10528 developed further in the trailing spot section (which could be classified as a region itself), however, opposite polarity spots increased their separation and the flare potential of the region has decreased somewhat. A minor M class flare is possible. Flares: C2.1 at 02:38, C1.1 at 04:57, C1.3 at 08:09 and C1.0 at 15:32 UTC.
Region 10530 decayed slowly and quietly. The region could become spotless today or tomorrow.
Region 10531 decayed and could soon become spotless.
December 21-23: 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
No obvious coronal holes will be rotating into geoeffective positions during the next few days.
Processed SOHO/EIT 284 image at 19:06 UTC on December 23. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on December 24-29.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor to fair. Propagation along long distance north-south paths is poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). Several US and Canadian east coast stations were heard on other frequencies].
|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|
why was this region
included by SEC?
classification was AXX
classification was BXO
at midnight, area 0020
classification was BXO
at midnight, area 0010
|Total spot count:||74||71|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.06||129.3||77.4||(65.1 predicted, -2.5)|
|2003.07||127.7||83.3||(61.8 predicted, -3.3)|
|2003.08||122.1||72.7||(58.8 predicted, -3.0)|
|2003.09||112.2||48.7||(56.9 predicted, -1.9)|
|2003.10||151.7||65.6||(54.1 predicted, -2.8)|
|2003.11||140.8||67.2||(51.4 predicted, -2.7)|
|2003.12||111.9 (1)||62.4 (2)||(48.9 predicted, -2.5)|
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.