Last major update issued on February 1, 2007 at 05:35 UTC.
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[Solar cycles 21-23 (last update January 11, 2007)]
[Solar cycles 1-20]
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[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update January 11, 2007)]
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[Archived reports (last update December 18, 2006)]
The geomagnetic field was unsettled on January 31. Solar wind speed ranged between 574 and 789 km/s (average speed was 697 km/s, increasing 31 km/s over the previous day) under the influence of a high speed stream from CH256.
Solar flux measured at 20h UTC on 2.8 GHz was 89.2. The planetary A index was 16 (STAR Ap - based on the mean of three hour interval ap indices: 16.1). Three hour interval K indices: 33333333 (planetary), 33443333 (Boulder).
The background x-ray flux is at the class A4 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10940 developed several new spots in the leading spot section
while the main penumbra was mostly unchanged. An M class flare in this region
could easily cause several nearby filaments to erupt.
Region 10941 was quiet and stable.
January 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 (CH256) in the southern hemisphere was in an Earth facing position on January 26-28.
Processed SOHO/EIT 195 image at 00:00 UTC on February 1. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on February 1-2 and quiet on February 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|
|10941||2007.01.29||1||1||S08E43||0150||HHX||classification was HSX at midnight|
|Total spot count:||12||17|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2006.07||75.7||12.2||(15.0 predicted, -1.3)|
|2006.08||79.0||12.9||(14.9 predicted, -0.1)|
|2006.09||77.8||14.5||(14.7 predicted, -0.2)|
|2006.10||74.3||10.4||(13.5 predicted, -1.2)|
|2006.11||86.3||21.5||(12.1 predicted, -1.4)|
|2006.12||84.5||13.6||(11.7 predicted, -0.4)|
|2007.01||83.3 (1)||28.2 (2)||(11.9 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.