Last major update issued on October 14, 2004 at 04:40 UTC.
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[Solar cycles 21-23 (last update October 2, 2004)]
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[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 2, 2004)]
[Historical solar and geomagnetic data charts 1954-2004 (last update August 28,
2004)]
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The geomagnetic field was unsettled to minor storm on October 13. Solar wind speed ranged between 370 and 520 km/sec under the influence of a stream from coronal hole CH118.
Solar flux measured at 20h UTC on 2.8 GHz was 87.1. The planetary A
index was 35 (STAR Ap - based on the mean of three hour interval ap indices: 32.8).
Three hour interval K indices: 45545433 (planetary), 55445433 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was low. A single C class event was recorded during the day.
Region 10681 decayed with the disappearance of the negative polarity area located inside the main positive polarity
area.
New region 10682 rotated into view at the southeast limb on October 12 and was numbered by SEC the next day. The region
developed during the day and has a weak magnetic delta structure at the southern end of the single penumbra. Flare:
C1.1 at 22:06 UTC.
October 11-13: No obviously Earth directed 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 recurrent coronal hole (CH118) in the southern hemisphere was in a geoeffective position on October 8-9. A poorly defined coronal hole (CH119) in the southern hemisphere could rotate into a geoeffective position on October 14.
Processed SOHO/EIT 284 image at 19:06 UTC on October 12. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on October 14-15 and mostly quiet on October 16.
| 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. When the high speed stream has arrived
the color changes to green.
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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor. Propagation along long distance north-south paths is fair. Trans Atlantic propagation conditions are monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). Several unidentified stations from Brazil were noted as well. On other frequencies propagation was best towards Brazil, Rádio Metropolitana on 930 kHz had a good signal. Only a few stations from North America could be heard. CJYQ on 930 had a fair signal while VOCM 590 and WWZN 1510 both had poor signals.
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. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.
| Active region | Date numbered | SEC spot count |
STAR spot count |
Location at midnight | Area | Classification | Comment |
|---|---|---|---|---|---|---|---|
| 10681 | 2004.10.12 | 9 | 5 | N11W21 | 0020 | CSO | |
| 10682 | 2004.10.13 | 12 | 8 | S13E64 | 0170 | CAO |
beta-delta formerly region S459 |
| Total spot count: | 21 | 13 | |||||
| SSN: | 41 | 33 | |||||
| Month | Average solar flux at Earth |
International sunspot number | Smoothed sunspot number |
|---|---|---|---|
| 2000.04 | 184.2 | 125.5 | 120.8 cycle 23 sunspot max. |
| 2000.07 | 202.3 | 170.1 | 119.8 |
| 2001.12 | 235.1 | 132.2 | 114.6 (-0.9) |
| 2003.08 | 122.1 | 72.7 | 60.0 (-1.7) |
| 2003.09 | 112.2 | 48.7 | 59.5 (-0.5) |
| 2003.10 | 151.7 | 65.5 | 58.2 (-1.3) |
| 2003.11 | 140.8 | 67.3 | 56.7 (-1.5) |
| 2003.12 | 114.9 | 46.5 | 54.8 (-1.9) |
| 2004.01 | 114.1 | 37.3 | 52.0 (-2.8) |
| 2004.02 | 107.0 | 45.8 | 49.3 (-2.7) |
| 2004.03 | 112.0 | 49.1 | 47.1 (-2.2) |
| 2004.04 | 101.2 | 39.3 | (44.6 predicted, -2.5) |
| 2004.05 | 99.8 | 41.5 | (40.9 predicted, -3.7) |
| 2004.06 | 97.4 | 43.2 | (38.0 predicted, -2.9) |
| 2004.07 | 119.1 | 51.0 | (36.2 predicted, -1.8) |
| 2004.08 | 109.6 | 40.9 | (34.6 predicted, -1.6) |
| 2004.09 | 103.1 | 27.7 | (32.8 predicted, -1.6) |
| 2004.10 | 89.4 (1) | 12.1 (2) | (30.5 predicted, -2.3) |
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 some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.
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