Last major update issued on January 1, 2007 at 06:25 UTC.
geomagnetic data - last month (updated daily)]
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[Solar cycles 21-23 (last update November 12, 2006)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 12, 2006)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update November 12, 2006)]
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[Archived reports (last update December 18, 2006)]
The geomagnetic field was very quiet on December 31. Solar wind speed ranged between 276 and 367 km/s (all day average 312 km/s - decreasing 33 km/s from the previous day). A weak coronal hole related disturbance appears to be in progress judging from ACE data early on January 1.
Solar flux measured at 20h UTC on 2.8 GHz was 83.3. The planetary A index was 1 (STAR Ap - based on the mean of three hour interval ap indices: 0.6). Three hour interval K indices: 00000001 (planetary), 00002111 (Boulder).
The background x-ray flux is at the class A5 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was low. A single C class event was recorded during the day.
Region 10933 was mostly unchanged. Further C class flares are possible.
Flare: C1.3 at 07:17 UTC.
New region 10934 rotated into view at the northeast limb on December 30 and was numbered the next day by SEC.
December 29-31: No obvious partly or fully Earth directed CMEs were detected in LASCO imagery.
history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A recurrent coronal hole (CH254) in the southern hemisphere was in an Earth facing position on December 30-31.
Processed SOHO/EIT 195 image at 00:00 UTC on January 1. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on January 1. A high speed wind from CH254 will likely cause unsettled to minor storm conditions on January 2-3.
|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) Effects from a CME are likely to be observed at 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.
Monitoring has been temporarily suspended (as of January 1, 2007).
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|
|10933||2006.12.30||4||6||S03E66||0210||CAO||classification was DAO at midnight|
|10934||2006.12.31||4||3||N04E64||0050||CRO||formerly region S686
classification was HAX at midnight
|Total spot count:||8||9|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2006.06||76.5||13.9||(16.3 predicted, -1.0)|
|2006.07||75.7||12.2||(14.7 predicted, -1.6)|
|2006.08||79.0||12.9||(14.2 predicted, -0.5)|
|2006.09||77.8||14.5||(14.1 predicted, -0.1)|
|2006.10||74.3||10.4||(13.0 predicted, -1.1)|
|2006.11||86.3||21.5||(11.5 predicted, -1.5)|
|2006.12||84.5 (1)||22.2 (2)||(11.3 predicted, -0.2)|
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% lower.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.