Last major update issued on October 18, 2005 at 03:55 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update October 2, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 2, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 2, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update October 2, 2005)]
The geomagnetic field was quiet to active on October 17. Solar wind speed ranged between 316 and 418 (all day average 365) km/sec under the influence of a low speed stream from CH192.
Solar flux measured at 20h UTC on 2.8 GHz was 78.1. The planetary
index was 13 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 34323311 (planetary), 34433321 (Boulder).
The background x-ray flux is at the class A3 level.
At midnight there was one spotted region on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10815 decayed slowly and quietly.
October 15-17: 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 recurrent coronal hole (CH193) in the southern hemisphere will likely rotate into an Earth facing position on October 21. CH193 did not cause any disturbance during the previous rotation.
Processed SOHO/EIT 284 image at 01:06 UTC on October 18. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on October 18, then become quiet on October 19-23. Quiet to active conditions are possible on October 24-25 due to effects from CH193.
|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. Propagation on long distance northeast-southwest paths is poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). Propagation was fairly good to Venezuela. Some stations from Cuba where noted as well. From North America the usual Newfoundland stations were audible, as were a few northeastern US stations.
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:||11||11|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2005.04||86.0||24.4||(31.9 predicted, -1.6)|
|2005.05||99.3||42.6||(29.4 predicted, -2.5)|
|2005.06||93.7||39.6||(28.1 predicted, -1.3)|
|2005.07||96.4||39.9||(26.9 predicted, -1.2)|
|2005.08||90.5||36.4||(25.0 predicted, -1.9)|
|2005.09||91.1||22.1||(23.0 predicted, -2.0)|
|2005.10||78.8 (1)||8.1 (2)||(21.0 predicted, -2.0)|
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.