Last major update issued on February 18, 2007 at 04:40 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-23 (last update January 11, 2007)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 11, 2007)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update January 11, 2007)]
[Historical solar and geomagnetic data charts 1954-2005 (last update March 3, 2006)]
[Archived reports (last update February 6, 2007)]
The geomagnetic field was quiet to unsettled on February 17. Solar wind speed ranged between 445 and 545 km/s (average speed was 478 km/s, decreasing 76 km/s from the previous day).
Solar flux measured at 20h UTC on 2.8 GHz was 75.3. The planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.6). Three hour interval K indices: 23111213 (planetary), 23113212 (Boulder).
The background x-ray flux is below the class A1 level.
At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was very low.
Region 10942 was quiet and stable.
February 15-17: No obvious partly or fully Earth directed CMEs were detected in LASCO imagery. At least a partial halo very assymmetrical CME was observed in LASCO C3 images starting at 15:42 UTC on February 17. The source of the CME was probably behind the central east limb.
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 will likely rotate into an Earth facing position on February 22-24.
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 mostly quiet on February 18-24.
|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|
|Total spot count:||1||1|
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||79.2 (1)||9.6 (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.