Last major update issued on December 27, 2003 at 05:10 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 26. Solar wind speed ranged between 347 and 406 km/sec. A weak disturbance was in progress most of the day.
Solar flux measured at 20h UTC on 2.8 GHz was 137.2. The planetary A
index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 10.1).
Three hour interval K indices: 22233323 (planetary), 22232333 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 2 spotted regions on the visible disk. Solar flare activity was moderate. A total of 4 C and 1 M class events were recorded during the day.
Region 10528 was mostly unchanged. The region became less active after the minor M class flare. Another M class flare is
possible. Flares: C7.1 at 10:40, C1.2 at 11:43, C1.0 at 12:09, C1.8 at 16:23 and M1.5/1N at
Region 10532 was quiet and stable.
December 24-26: 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 recurrent trans equatorial coronal hole (CH73) will rotate into a geoeffective position on December 28-29.
Processed SOHO/EIT 284 image at 19:06 UTC on December 26. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled until December 31 when a high speed stream from coronal hole CH73 is likely to cause unsettled to minor storm conditions.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes was fair to good early in the night, then became fair. Propagation along long distance north-south paths is fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). Several other stations noted including WLAM Lewiston ME. On other frequencies stations from Colombia and Venezuela were generally much better compared to the situation one day ago].
|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|
classification was FKI
|Total spot count:||45||46|
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||115.0 (1)||69.9 (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.