Last update issued on September 23, 2003 at 03:50 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 16, 2003)]
The geomagnetic field was quiet to active on September 22. Solar wind speed ranged between 496 and 642 km/sec under the influence of a high speed stream from coronal hole CH59.
Solar flux measured at 20h UTC on 2.8 GHz was 121.6. The planetary A
index was 18 (STAR Ap - based on the mean of three hour interval ap indices: 18.9).
Three hour interval K indices: 34444342 (planetary), 24343342 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 6 spotted regions on the visible disk. Solar flare activity was very low.
Region 10459 decayed and had only a couple of small spots left by midnight. The region will be rotating over the
southwest limb today and tomorrow.
Region 10463 was quiet and stable.
Region 10464 added a few spots and simplified magnetically in the leading spot section. While the region is moderately large and could be capable of M class flaring, it is currently quiet.
New region 10465 was split off from region 10464 and seemed to be decaying late in the day.
New region 10466 rotated partially into view at the southeast limb on September 21 and developed on September 22. There is not much separating the positive and negative polarity fields and further development is likely.
Spotted regions not numbered by NOAA/SEC:
[S260] A new region emerged in the northern hemisphere near the central meridian on September 22. Location at midnight: N15W03.
September 20-22: No potentially geoeffective CMEs observed. Large backsided halo CMEs were observed on both September 20 and 21.
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
An elongated coronal hole (CH59) in the southern hemisphere was in a geoeffective position on September 18-21. A coronal hole (CH60) in the northern hemisphere is currently rotating into view at the east limb.
Processed SOHO/EIT 184 image at 01:06 UTC on September 23. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active until September 24 due to a high speed stream from coronal hole CH59. Quiet to unsettled is likely on September 25-27.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor. Propagation along north-south paths is poor to very poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Cadena Peruana de Noticias with a weak signal. This station had a strong signal during the otherwise poor sunrise opening on September 21].
|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 AXX
at midnight, area 0010
classification was HRX
at midnight, area 0020
formerly region S259
classification was DAO
at midnight, area 0110
|Total spot count:||31||41|
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||105.0 (1)||48.5 (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.