Last update issued on October 8, 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 October 4, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 4, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 4, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update July 23, 2003)]
[Archived reports (last update October 7, 2003)]
The geomagnetic field was quiet to active on October 7. Solar wind speed ranged between 481 and 650 km/sec under the influence of a high speed stream from coronal hole CH61.
Solar flux measured at 20h UTC on 2.8 GHz was 111.9. The planetary A
index was 13 (STAR Ap - based on the mean of three hour interval ap indices: 14.1).
Three hour interval K indices: 42233333 (planetary), 51243332 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 3 spotted regions on the visible disk. Solar flare activity was low. A total of 2 C class events was recorded during the day.
Region 10471 added some area to the largest penumbrae while some of the smaller spots disappeared. Flares:
C1.8 at 17:43 and C3.2 at 23:57 UTC.
Region 10473 lost a few of the small trailing spots and was quiet..
Region 10477 developed slowly and quietly.
October 5-6: No potentially geoeffective CMEs observed. No LASCO images available for October 7.
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
There is a small coronal hole in the northern hemisphere which will rotate across the central meridian on October 8. This coronal hole is likely too far to the north to become geoeffective. A trans equatorial area with weak corona will rotate to the central meridian on October 9-10.
Processed SOHO/EIT 284 image at 23:50 UTC on October 7. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled October 8-13.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along north-south paths is fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Vibración (Venezuela)].
|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 DAO
|Total spot count:||36||35|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.04||126.4||60.0||(69.6 predicted, -4.5)|
|2003.05||115.7||55.2||(65.3 predicted, -4.3)|
|2003.06||129.3||77.4||(61.5 predicted, -3.8)|
|2003.07||127.7||85.0||(58.0 predicted, -3.5)|
|2003.08||122.1||72.7||(55.0 predicted, -3.0)|
|2003.09||112.2||48.8||(53.0 predicted, -2.0)|
|2003.10||119.2 (1)||21.4 (2)||(50.3 predicted, -2.7)|
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.