Last major update issued on February 12, 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 on February 11. Solar wind speed ranged between 272 and 368 km/s (average speed was 294 km/s, decreasing 60 km/s from the previous day).
Solar flux measured at 20h UTC on 2.8 GHz was 74.7. The planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.4). Three hour interval K indices: 01000122 (planetary), 01000011 (Boulder).
The background x-ray flux is far below the class A1 level.
At midnight the visible solar disk was spotless. The solar flare activity level was very low. No C class events were recorded during the day.
February 9-11: 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
The main part of recurrent coronal hole (CH257) will be in an Earth facing position on February 11-12. The leading western part has nearly closed. CH257 has a trans equatorial extension stretching northeastward from the northernmost point of the main coronal hole.
Processed SOHO/EIT 195 image at 00:36 UTC on February 12. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on February 12 and part of February 13 due to weak effects from CH257. Unsettled to minor storm conditions are possible from sometime on February 13 until February 15 as the high speed stream from the eastern part of CH257 becomes the main solar wind source.
|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 10, 2007: Several stations from the Canadian Atlantic provinces had strong signals while stations further south and west were weaker than expected.
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:||0||0|
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||82.2 (1)||8.8 (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.