Last major update issued on December 17, 2003 at 04:00 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 8, 2003)]
The geomagnetic field was quiet to unsettled on December 16. Solar wind speed ranged between 474 and 713 km/sec, gradually decreasing all day.
Solar flux measured at 20h UTC on 2.8 GHz was 106.3. The planetary A
index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 12.9).
Three hour interval K indices: 33333332 (planetary), 23333332 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 7 spotted regions on the visible disk. Solar flare activity was low.
Region 10520 decayed and lost quite a few spots as well as penumbral area, particularly in the leading spot section.
Region 10521 decayed slowly and quietly.
New region 10523 rotated into view at the southeast limb. Flare: C1.0 at 13:25 UTC.
New region 10524 emerged near the southeast limb with a few small spots.
New region 10525 rotated into view at the northeast limb. This region was the source of a C8.6 flare at 03:13 UTC on December 17.
Spotted regions not numbered by NOAA/SEC:
[S322] This region was first observed on December 13. No spots were observed on Dec.14 and 15. Then, on December 16, the region reemerged with several spots. Location at midnight: S15W27.
[S324] A new region emerged on December 16 in the northwest quadrant. Location at midnight: N12W41.
December 14-16: 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 coronal hole in the northern hemisphere (CH72) with a trans equatorial extension will rotate into a geoeffective position on December 17-19.
Processed SOHO/EIT 284 image at 19:06 UTC on December 16. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on December 17, 18 and the first half of Dec.19. From the latter half of Dec.19 until Dec.22 a high speed stream from coronal hole CH72 will dominate the solar wind.
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. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay, Radio Rafaela (Argentina) and Radio Vibración (Venezuela). WDHP on 1620 kHz had a good signal tonight].
|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 0110
classification was CRO
classification was CSO
|Total spot count:||21||31|
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||104.4 (1)||35.8 (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.