Last major update issued on October 1, 2005 at 02:55 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 to active on September 30. Solar wind speed ranged between 320 and 478 (all day average 376) km/sec. The high speed stream from CH189 arrived near noon and caused a minor geomagnetic disturbance.
Solar flux measured at 20h UTC on 2.8 GHz was 72.2. The planetary
index was 11 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 12134322 (planetary), 12134211 (Boulder).
The background x-ray flux is at the class A2 level.
At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Spotted regions not numbered by NOAA/SEC:
[S595] This region emerged quickly in the northwest quadrant late in the day. The region is currently magnetically simple. Location at midnight: N12W15.
September 28-30: 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.
Processed SOHO/EIT 284 image at 01:06 UTC on October 1. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on October 1 and quiet October 2-9.
|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: At 23h UTC Radio Cristal del Uruguay and Rádio Rural AM de Parelhas (Brazil) with strong signals, later on Radio Vibración (Venezuela) dominated and an unidentified stations from Colombia was observed. There were lots of stations from Venezuela and Colombia on other frequencies. From North America some of the stations in the US northeast and on Newfoundland were heard with good signals. The beverage antenna directed to the southwest had strong signals from 1510 Radio San Carlos (Uruguay) and 930 Radio Monte Carlo (Uruguay).
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:||3||7|
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||91.1 (1)||39.2 (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.