Last update issued on September 11, 2003 at 03:35 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 10. Solar wind speed ranged between 569 and 808 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 99.3. The planetary A
index was 19 (STAR Ap - based on the mean of three hour interval ap indices: 19.5).
Three hour interval K indices: 42343343 (planetary), 42243443 (Boulder).
The background x-ray flux is at the class B2-B3 level.
At midnight there were 3 spotted regions on the visible disk. Solar flare activity was very low.
Region 10456 developed quickly during the latter half of the day with new flux emerging centrally and to the north.
Polarities are intermixed and development of penumbra in the central section could easily cause a magnetic delta structure to
form. A minor M class flare will become possible if the current rate of development is sustained.
Region 10457 was quiet and stable.
Spotted regions not numbered by NOAA/SEC:
[S253] A new bipolar region emerged in the southeast quadrant on September 10 due east of region 10457. Location at midnight: S11E00.
September 8-10: 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. Another trans equatorial coronal hole (CH56) will likely rotate into a geoeffective position on September 12-13. A recurrent coronal hole (CH57) in the southern hemisphere and with a trans equatorial extension will rotate into a geoeffective position on September 14-17.
Processed SOHO/EIT 284 image from 01:06 UTC on September 11. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active, possibly with isolated minor storm intervals, until September 12 under the influence of a high speed stream from coronal hole CH55. Quiet to unsettled is likely on September 13-15. High speed stream from coronal holes CH56 and CH57 will likely cause unsettled to active conditions on September 16-18 and unsettled to minor storm on September 19-22.
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 (Propagation was briefly good to excellent during local sunrise on Sept.10 when many stations from Argentina and a few from Peru were heard). [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: 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|
classification was AXX
|Total spot count:||22||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||105.1 (1)||19.9 (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.