Last major update issued on February 26, 2007 at 04:35 UTC.
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[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update January 11, 2007)]
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The geomagnetic field was quiet on February 25. Solar wind speed ranged between 270 and 346 km/s (average speed was 294 km/s, increasing 21 km/s from the previous day) in very incomplete SOHO data. Solar wind speed increased gradually after 19h UTC as a high speed stream from CH258 arrived.
Solar flux measured at 20h UTC on 2.8 GHz was 76.6. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.8). Three hour interval K indices: 11000121 (planetary), 11102221 (Boulder).
The background x-ray flux is below the class A1 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 10944 was quiet and stable.
Spotted regions not numbered by NOAA/SEC:
[S696] This region rotated into view at the southeast limb on February 25. Location at midnight: S06E74
February 23-25: 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 (CH258) in the southern hemisphere was in an Earth facing position on February 22-25.
Processed SOHO/EIT 195 image at 21:37 UTC on February 13. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to minor storm on February 26-27 and quiet to active on February 28 due to a high speed stream from CH258.
|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.
Daily monitoring will not resume until a local noise problem (related to construction work on a neighboring property) has been fixed. Occasional monitoring reports will be submitted when propagation is good.
February 18, 2007: Strong signals were noted from a number of USA east coast stations as well as from stations located in the Canadian Atlantic provinces. CFDR on 780 kHz was particularly strong.
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|
|10944||2007.02.22||2||2||S08E37||0110||HSX||classification was CSO at midnight, area 0080|
|Total spot count:||2||5|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2006.08||79.0||12.9||(15.6 predicted, +0.3)|
|2006.09||77.8||14.5||(15.7 predicted, +0.1)|
|2006.10||74.3||10.4||(14.5 predicted, -1.2)|
|2006.11||86.3||21.5||(12.8 predicted, -1.7)|
|2006.12||84.5||13.6||(12.1 predicted, -0.7)|
|2007.01||83.3||16.9||(12.0 predicted, -0.1)|
|2007.02||78.0 (1)||14.9 (2)||(12.1 predicted, +0.1)|
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.