Last update issued on September 8, 2003 at 03:35 UTC.
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[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)]
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The geomagnetic field was quiet to unsettled on September 7. Solar wind speed ranged between 387 and 549 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 107.8. The planetary A
index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.4).
Three hour interval K indices: 33123333 (planetary), 22222321 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 2 spotted regions on the visible disk. Solar flare activity was low. A total of 3 C class events were recorded during the day. A long duration C4.2 event peaked at 14:35 UTC and appears to have been associated with a filament eruption near region 10450. A small CME was observed off of the southwest limb after this event. A long duration C1.4 event peaked near 16:40 UTC and was associated with a filament eruption at high latitudes in the southwest quadrant. A bright CME was observed beginning at 18:18 UTC in LASCO C3 images following this event. At this time the CME does not appear likely to reach the Earth.
Region 10450 decayed and became spotless after a C flare. Flare: C5.8 at 14:07 UTC.
Region 10453 rotated partly out of view at the southwest limb.
Spotted regions not numbered by NOAA/SEC:
[S251] A new region emerged in the southeast quadrant on September 7 due north of spotless region 10455. Location at midnight: S08E23.
September 5-7: 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) will rotate into a geoeffective position on September 6-8.
Processed SOHO/EIT 284 image from 01:06 UTC on September 8. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled during the first half of September 9, then a high speed stream from coronal hole CH55 is likely to cause unsettled to minor storm conditions until September 11.
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 poor to fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: 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 HAX
|Total spot count:||14||6|
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||108.2 (1)||15.1 (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.