Last major update issued on October 14, 2007 at 02:45 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-23 (last update October 4, 2007)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 4, 2007)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 4, 2007)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports (last update October 3, 2007)]
The geomagnetic field was quiet on October 13. Solar wind speed ranged between 299 and 334 km/s (average speed was 315 km/s, increasing 18 km/s from the previous day) under the influence of a low speed stream from CH294.
Solar flux measured at 20h UTC on 2.8 GHz was 67.6. The planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.8). Three hour interval K indices: 00001101 (planetary), 00002211 (Boulder).
The background x-ray flux is 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.
October 11-13: No obvious fully or partly Earth directed CMEs were observed 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 (CH294) in the southern hemisphere was in an Earth facing position on October 8-10. CH294 has become better defined over the last solar rotation, although most of the coronal hole is too far to the south to influence Earth. A recurrent trans equatorial hole (CH295) will likely rotate into an Earth facing position on October 16-18. CH295 is poorly defined in the western part. The development of an active region in the southeastern part of the coronal hole has diminished its area significantly.
Processed SOHO/EIT 195 image at 10:00 UTC on October 13. The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is good to very good. Propagation on long distance northeast-southwest paths is poor.
Monitoring remarks from a location near N58E06: October 13-14: Stations from the Canadian Atlantic provinces had strong signals when listening started at 21:30 UTC. A few USA stations were present and 1370 WDEA was strong that early. Within an hour nearly all TA frequencies had good to strong signals from North America. 1510 WLAC was noted at 22:40 UTC on a lively channel while 1310 CIWW was dominant at 22:10 UTC. The best Trans Atlantic propagation sector was 270-310 degrees.
The geomagnetic field is expected to be mostly quiet October 14-18. Some unsettled and active intervals are likely on October 19-21 due to a high speed stream from CH295.
|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.
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.
|2007.04||72.4||3.7||(10.1 predicted, -0.7)|
|2007.05||74.4||11.7||(9.0 predicted, -1.1)|
|2007.06||73.7||12.0||(8.0 predicted, -1.0)|
|2007.07||71.6||10.0||(7.3 predicted, -0.7)|
|2007.08||69.1||6.2||(6.8 predicted, -0.5)|
|2007.09||67.1||2.4||(6.9 predicted, +0.1)|
|2007.10||68.0 (1)||1.3 (2)||(7.6 predicted, +0.7)|
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.