Last update issued on October 11, 2003 at 03:45 UTC.
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[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)]
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The geomagnetic field was quiet on October 10. Solar wind speed ranged between 408 and 517 km/sec. The interplanetary magnetic field was northwards most of the day, only a few brief and weak southwards excursions were observed.
Solar flux measured at 20h UTC on 2.8 GHz was 111.8. The planetary A
index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 6.1).
Three hour interval K indices: 21122212 (planetary), 00003221 (Boulder).
The background x-ray flux is at the class B2-B3 level.
At midnight there were 6 spotted regions on the visible disk. Solar flare activity was very low.
Region 10471 decayed further and was quiet.
Region 10473 was quiet and stable and will be rotating out of view late today.
Region 10477 was mostly unchanged and quiet.
Region 10478 decayed and became spotless early in the day, then reemerged with a couple of spots during the last hours of the day.
New region 10479 rotated into view at the northeast limb on October 9 and was numbered by SEC the next day.
Spotted regions not numbered by NOAA/SEC:
[S276] A new region emerged in the northwest quadrant on October 10. Location at midnight: N07W65.
October 8-10: No potentially geoeffective CMEs observed. Three successive CMEs from a location several days behind the northeast limb were observed on October 9.
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 recurrent trans equatorial coronal hole (CH62) was in a geoeffective position on October 10. Another recurrent trans equatorial hole (CH63) will rotate into a geoeffective position on October 12-14.
Processed SOHO/EIT 284 image at 14:06 UTC on October 10. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet on October 11-12. Quiet to active is likely on October 13-14 due to a high speed stream from coronal hole CH62 with a high speed stream from coronal hole CH63 causing unsettled to minor storm conditions on October 15-17.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is fair to good. Propagation along north-south paths is fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). Several North American stations heard on other frequencies with an impressive signal from WWZN Boston on 1510 kHz].
|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
classification was HSX
HHX classification is not
possible with area less
classification was HRX
formerly region S275
classification was CSO
|Total spot count:||29||25|
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||117.0 (1)||28.4 (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.