Last update issued on September 10, 2003 at 03:25 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 active on September 9. Solar wind speed ranged between 444 and 717 km/sec under the influence of a high speed stream from coronal hole CH55.
Solar flux measured at 20h UTC on 2.8 GHz was 95.9. The planetary A
index was 19 (STAR Ap - based on the mean of three hour interval ap indices: 20.0).
Three hour interval K indices: 22344344 (planetary), 32344345 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 2 spotted regions on the visible disk. Solar flare activity was very low.
Region 10456 developed early in the day with some intermixing of polarities. Slow decay was observed late in the day as
the positive and negative polarity areas drifted apart.
New region 10457 emerged on September 8 in the southeast quadrant and was numbered the next day by SEC.
September 7-9: 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 10. 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 very poor (propagation became good during a local sunrise opening on Sept.9 with lots of stations from the US and Canadian east coast). Propagation along north-south paths is poor to fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay early on, then an unidentified station from Perú, probably CPN].
|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|
classification was DAI
at midnight, area 0080
formerly region S252
classification was AXX
|Total spot count:||23||17|
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||105.8 (1)||18.5 (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.