Last major update issued on October 10, 2007 at 01:25 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 9. Solar wind speed ranged between 279 and 307 km/s (average speed was 292 km/s, decreasing 3 km/s from the previous day).
Solar flux measured at 20h UTC on 2.8 GHz was 68.7. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.1). Three hour interval K indices: 10002111 (planetary), 10111101 (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 7-9: 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 could rotate into 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.
Processed SOHO/EIT 195 image at 21:36 UTC on October 9. 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 very good. Propagation on long distance northeast-southwest paths is poor.
Monitoring remarks from a location near N58E06: October 8-9: Listening started at 21:40 UTC. Several east coast USA stations were already audible and 1510 actually had a good signal. Within an hour signals were present on almost all trans Atlantic frequencies. Stations like 1490 WBAE and 1370 WDEA were unusually strong and 1470 kHz had several stations surfacing in addition to the signals of WLAM and WWNN. WNWR was noted on 1540 kHz before signing off. At LSR on Oct.9 conditions were very good. 1330 kHz had 5-6 stations with WLOL the best with excellent peaks. KWLO was there as well, as was the normally dominant WRCA. KOMO was strong on 1000 kHz and many frequencies had simply too many signals. The best Trans Atlantic propagation sector was 270-310 degrees.
The geomagnetic field is expected to be generally quiet October 10-16. A few unsettled and active intervals are possible on October 11-13 due to effects from CH294.
|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||67.7 (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.