Last major update issued on February 17, 2006 at 03:55 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update February 4, 2006)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update February 4, 2006)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update February 4, 2006)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update February 7, 2006)]
The geomagnetic field was quiet to unsettled on February 16. Solar wind speed ranged between 463 and 598 (all day average 534 km/sec under the decreasing influence of a high speed stream from CH211.
Solar flux measured at 20h UTC on 2.8 GHz was 79.2. The
planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 32331012 (planetary), 22432101 (Boulder).
The background x-ray flux is at 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 10854 decayed in the trailing spot section.
New region 10855 emerged near the northeast limb on February 13 and was finally noticed by SEC three days later. The region decayed slowly on February 16.
February 14-16: No obviously fully or partly Earth directed CMEs were 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 (CH212) in the northern hemisphere will be in an Earth facing position on February 17.
Processed SOHO/EIT 284 image at 01:06 UTC on February 17. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on February 17 and quiet on February 18-19. Unsettled conditions are likely again on February 20-21 due to effects from CH212.
|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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). Only a few stations from North America were audible. Interestingly Greenland was heard on 650 kHz with an unusually strong signal.
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|
|10854||2006.02.15||6||3||S07E10||0030||DAO||classification was CSO at midnight|
|10855||2006.02.16||1||2||N06E28||0020||HAX||formerly region S624
classification was BXO at midnight, area 0000
|Total spot count:||7||5|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2005.08||90.5||36.4||(27.6 predicted, -1.5)|
|2005.09||91.1||22.1||(25.8 predicted, -1.8)|
|2005.10||77.0||8.5||(24.0 predicted, -1.8)|
|2005.11||86.3||18.0||(21.6 predicted, -2.4)|
|2005.12||90.7||41.2||(18.7 predicted, -2.9)|
|2006.01||83.4||15.4||(15.6 predicted, -3.1)|
|2006.02||76.4 (1)||3.3 (2)||(12.5 predicted, -3.1)|
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.