Last major update issued on October 2, 2006 at 03:25 UTC.
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The geomagnetic field was quiet to minor storm on October 1. Solar wind speed ranged between 384 and 564 km/s (all day average 488 km/s - increasing 122 km/s over the previous day) under the influence of a high speed stream from CH241.
Solar flux measured at 20h UTC on 2.8 GHz was 78.4. The planetary A index was 25 (STAR Ap - based on the mean of three hour interval ap indices: 25.3). Three hour interval K indices: 55443313 (planetary), 45553222 (Boulder).
The background x-ray flux is at the class A2 level.
At midnight there were 3 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 10913 was quiet and stable.
Region 10914 was quiet and stable.
Region 10915 decayed slowly and will be rotating over the southwest limb late today.
September 29 - October 1: No obvious partly or fully Earth directed CMEs were detected in incomplete LASCO imagery.
Coronal hole 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 small coronal hole (CH242) in the northern hemisphere will likely rotate into an Earth facing position on October 4. A review of images from the previous solar rotation reveals that this coronal hole was present even then and was the likely source of a few unsettled intervals on September 11. During that time a minor increase in solar wind speed to a peak of 388 km/sec was observed.
Processed SOHO/EIT 284 image at 14:06 UTC on September 29. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be mostly quiet on October 2-10. Some unsettled intervals are possible on October 8 due to effects from a low speed stream from CH242.
|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 very poor to poor. Propagation on long distance northeast-southwest paths is fair.
Only a stations from North American were audible during the night, 800 VOWR and 1510 WWZN were both noted with poor to occasionally fair signals. Several stations from Argentina had good signals, 1190 Radio América, 1270 Radio Provincia and 1350 Radio Buenos Aires were all impressive.
During the hour after LSR on October 1 a number of stations from Venezuela were audible with fair to good signals. One example is 660 Ondas de los Médanos which was better than I've heard them in a long time.
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|
|10913||2006.09.28||2||3||S19E27||0040||CSO||classification was HAX at midnight, area 0070|
|10914||2006.09.28||1||1||S10E36||0030||HSX||area was 0020 at midnight|
|10915||2006.09.29||2||3||S05W72||0060||DSO||classification was CRO at midnight, area 0020|
|Total spot count:||5||7|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2006.04||89.0||30.2||(17.1 predicted, -0.2)|
|2006.05||80.9||22.2||(16.8 predicted, -0.3)|
|2006.06||76.5||13.9||(15.1 predicted, -1.7)|
|2006.07||75.7||12.2||(13.2 predicted, -1.9)|
|2006.08||79.0||12.9||(12.8 predicted, -0.4)|
|2006.09||77.8||14.5||(12.6 predicted, -0.2)|
|2006.10||78.4 (1)||1.1 (2)||(11.6 predicted, -1.0)|
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.