Last update issued on September 9, 2003 at 03:00 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update September 1, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update September 1, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update September 1, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update July 23, 2003)]
[Archived reports (last update September 8, 2003)]
The geomagnetic field was quiet to unsettled on September 8. Solar wind speed ranged between 363 and 487 km/sec. A high speed stream from coronal hole CH55 began influencing the geomagnetic field after 17h UTC.
Solar flux measured at 20h UTC on 2.8 GHz was 98.8. The planetary A
index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 10.4).
Three hour interval K indices: 21223333 (planetary), 11123334 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 2 spotted regions on the visible disk. Solar flare activity was very low.
New region 10456 emerged in the southeast quadrant on September 7 and was numbered by SEC the following day. The region developed slowly on September 8.
Spotted regions not numbered by NOAA/SEC:
[S252] A new region emerged in the southeast quadrant on September 8. Slow decay was observed late in the day. Location at midnight: S11E22.
September 6-8: No potentially geoeffective CMEs observed.
Coronal hole 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 trans equatorial coronal hole (CH55) was in a geoeffective position on September 6-8.
Processed SOHO/EIT 284 image from 01:06 UTC on September 9. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to minor storm until September 11 under the influence of a high speed stream from coronal hole CH55. Quiet to active is likely on September 12 with quiet to unsettled expected for September 13-16.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor (propagation became fair to good during a local sunrise opening on Sept.8). Propagation along north-south paths is poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela) at first, then Radio Cristal del Uruguay].
|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.
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.
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.
|Solar region||Date numbered||SEC
|Location at midnight||Area||Classification||Comment|
|10453||2003.09.04||1||S24W91||0090||HSX||rotated out of view|
|10456||2003.09.08||10||10||S09E08||0030||DSO||formerly region S251|
|Total spot count:||18||12|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.03||131.4||61.1||(74.2 predicted, -4.3)|
|2003.04||126.4||60.0||(69.3 predicted, -4.9)|
|2003.05||115.7||55.2||(64.4 predicted, -4.9)|
|2003.06||129.3||77.4||(60.4 predicted, -4.0)|
|2003.07||127.7||85.0||(56.9 predicted, -3.5)|
|2003.08||122.1||72.7||(53.9 predicted, -3.0)|
|2003.09||107.0 (1)||17.1 (2)||(51.9 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% less.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.