Last major update issued on September 16, 2005 at 03:30 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 severe storm on September 15. Solar wind speed ranged between 529 and 960 (all day average 711) km/sec. The leading edge of the CME seen late on September 13 in LASCO images was observed at ACE near 08:35 UTC. There was no proper solar wind shock, however, solar wind speed increased from 550 to 960 km/sec over the next few hours. The geomagnetic disturbance was less intense than had been forecast.
Solar flux measured at 20h UTC on 2.8 GHz was 119.4. The planetary
index was 43 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 32356754 (planetary), 42345653 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was high. A total of 11 C, 2 M and 1 X class events was recorded during the day.
Region 10808 decayed further in the trailing spot section and lost spots in the leading spot section immediately ahead of the major penumbra. The main penumbra remains very complex with the negative polarity area in the southern half continuing its westward movement. Another major proton flare is possible as long as the strong delta in the major penumbra persists. Flares: C8.5/1N long duration event peaking at 01:19, M1.3 at 02:12, C2.6 at 05:00, C1.8 at 06:53, impulsive X1.1/2N at 08:38, C1.0 at 10:42, C1.0 at 14:37, C7.1 at 15:17, C5.2 at 15:35, C1.1 at 16:20, C4.8 at 16:51, C2.3 at 18:30, M1.0 at 19:10 and C1.5 at 20:39 UTC. Early on September 16 an M4.4 flare was recorded at 01:49 and an M2.1 event at 02:14 UTC.
September 15: There may have one or two smaller Earth directed CMEs associated with M and X class flares. LASCO data for the day is incomplete.
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
Coronal holes cannot currently be reliably observed as the relevant GOES SXI, TRACE and SOHO data are all unavailable.
Processed TRACE mosaic image on September 6, 2005. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to minor storm on September 16 and quiet to minor storm on September 17-18.
|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 very poor. Propagation on long distance northeast-southwest paths is poor to very poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay with a very poor signal.
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:||67||40|
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||96.2 (1)||22.9 (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.