Last major update issued on September 30, 2005 at 03:20 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update September 3, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update September 3, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update September 3, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update September 14, 2005)]
The geomagnetic field was quiet on September 29. Solar wind speed ranged between 328 and 392 (all day average 358) km/sec. The average solar wind density is slowly decreasing but is still above average. The high speed stream associated with CH189 has not arrived and currently appears unlikely to arrive. CH189 has decayed since before crossing the central meridian and seems to have closed completely.
Solar flux measured at 20h UTC on 2.8 GHz was 73.8. The planetary
index was 6 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 21122211 (planetary), 22223222 (Boulder).
The background x-ray flux is at the class A1-A2 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 10810 was quiet as it rotate to the northwest limb.
Region 10812 was quiet and stable.
September 27-29: No obvious fully or partly Earth directed CMEs were observed.
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 small recurrent coronal hole (CH190) in the northern hemisphere could rotate to an Earth facing position on October 2. CH190 is unimpressive and may be in the process of closing completely.
Processed SOHO/EIT 284 image at 01:06 UTC on September 30. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet on September 30 - October 9. Several coronal holes have either disappeared or become insignificant over the last solar rotation.
|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) Material from a CME is likely to impact 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 to fair. Propagation on long distance northeast-southwest paths is good. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Vibración (Venezuela). On other frequencies most of the stations heard were from Venezuela and Colombia. 1420 Radio Marabina (Venezuela) was excellent. Several stations from North America were audible with some of the Newfoundland stations having excellent signals. Propagation to North America could improve to very good or excellent over the next few days.
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:||2||2|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2005.03||89.9||24.5||(33.5 predicted, -0.4)|
|2005.04||86.0||24.4||(32.2 predicted, -1.3)|
|2005.05||99.3||42.6||(29.9 predicted, -2.3)|
|2005.06||93.7||39.6||(28.7 predicted, -1.2)|
|2005.07||96.4||39.9||(27.7 predicted, -1.0)|
|2005.08||90.5||36.4||(25.8 predicted, -1.9)|
|2005.09||91.7 (1)||38.8 (2)||(24.2 predicted, -1.6)|
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.