Last major update issued on December 14, 2003 at 04:35 UTC.
[Solar and geomagnetic data - last month (updated daily)]
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[Solar cycles 21-23 (last update December 2, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update December 2, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update December
2, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update October 15, 2003)]
[Archived reports (last update December 8, 2003)]
The geomagnetic field was unsettled to minor storm on December 13. Solar wind speed ranged between 619 and 853 km/sec under the influence of a high speed stream from coronal hole CH71.
Solar flux measured at 20h UTC on 2.8 GHz was 87.8. The planetary A
index was 28 (STAR Ap - based on the mean of three hour interval ap indices: 28.8).
Three hour interval K indices: 54445543 (planetary), 54434533 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 4 spotted regions on the visible disk. Solar flare activity was very low.
Region 10520 developed with both positive and negative flux emerging ahead of the dominant negative polarity spot. C
class flares are possible.
Region 10521 was quiet and stable.
New region 10522 emerged in the northwest quadrant on December 12 and was numbered by NOAA/SEC the next day.
Spotted regions not numbered by NOAA/SEC:
[S322] A new region emerged in the southeast quadrant early on December 13. Slow decay was observed late in the day. Location at midnight:
S15E11.
December 11-13: No partly or fully 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 huge recurrent trans equatorial coronal hole (CH71) was in a geoeffective position on December 5-11. Some decay was observed in the northern and western parts on December 9-10 and in the central southern and western parts on December 11-12. A recurrent coronal hole in the northern hemisphere (CH72) will likely rotate into a geoeffective position on December 17.
Processed SOHO/EIT 284 image at 01:06 UTC on December 14. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to minor storm on December 14 due to a high speed stream from coronal hole CH71. Quiet to active is expected for December 15 with quiet to unsettled likely on December 16-18.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along long distance north-south paths is fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay. While there were other stations audible at times, weather related static made listening difficult].
| 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.
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 |
|---|---|---|---|---|---|---|---|
| 10520 | 2003.12.10 | 1 | 12 | N02E33 | 0110 | HSX |
beta-gamma classification was DSO at midnight, area 0140 |
| 10521 | 2003.12.10 | 4 | 5 | S12E34 | 0080 | DSO |
classification was DAO at midnight |
| 10522 | 2003.12.13 | 5 | 4 | N16W50 | 0020 | CSO | formerly region S321 |
| S322 | emerged on 2003.12.13 |
1 | S15E11 | 0000 | AXX | ||
| Total spot count: | 10 | 22 | |||||
| SSN: | 40 | 62 | |||||
| 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) |
| 2002.11 | 168.7 | 95.5 | 85.2 (-5.3) |
| 2002.12 | 157.2 | 80.8 | 82.0 (-3.2) |
| 2003.01 | 144.0 | 79.7 | 80.9 (-1.1) |
| 2003.02 | 124.5 | 46.0 | 78.5 (-2.4) |
| 2003.03 | 131.4 | 61.1 | 74.1 (-4.4) |
| 2003.04 | 126.4 | 60.0 | 70.3 (-3.8) |
| 2003.05 | 115.7 | 55.2 | 67.8 (-2.5) |
| 2003.06 | 129.3 | 77.4 | (65.3 predicted, -2.5) |
| 2003.07 | 127.7 | 85.0 | (61.9 predicted, -3.4) |
| 2003.08 | 122.1 | 72.7 | (59.0 predicted, -2.9) |
| 2003.09 | 112.2 | 48.8 | (57.0 predicted, -2.0) |
| 2003.10 | 151.7 | 65.6 | (54.3 predicted, -2.7) |
| 2003.11 | 140.8 | 67.2 | (51.6 predicted, -2.7) |
| 2003.12 | 105.5 (1) | 30.6 (2) | (49.0 predicted, -2.6) |
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.
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