Last major update issued on January 5, 2005 at 04:00 UTC.
[Solar and geomagnetic data - last month (updated daily)]
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[Solar cycles 21-23 (last update January 2, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 2, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update January
2, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update November 8,
2004)]
[Archived reports (last update January 2, 2005)]
The geomagnetic field was unsettled to active on January 4. Solar wind speed ranged between 612 and 860 km/sec under the influence of a high speed stream from coronal hole CH136.
Solar flux measured at 20h UTC on 2.8 GHz was 88.0. The planetary A
index was 23 (STAR Ap - based on the mean of three hour interval ap indices: 22.8).
Three hour interval K indices: 44344433 (planetary), 44243433 (Boulder).
The background x-ray flux is at the class A5 level.
At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was low. A total of 3 C class events was recorded during the day.
Region 10715 decayed further. Occasional C flares are still possible. Flares: C1.0 at 01:58, C3.3 at 06:16 and C7.3 at 11:13 UTC.
January 4: An extremely faint and slow full halo CME was observed in LASCO C3 images after noon. This CME was likely
associated with a C7 flare in region 10715.
January 3: An extremely faint and slow full halo CME was observed in LASCO C3 images after 09h UTC. If there was a
frontsided source the only candidate would have been the C3 LDE in region 10715 a few hours earlier.
January 2: No obviously Earth directed CMEs were 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
Recurrent large trans equatorial coronal hole CH136 was in a geoeffective position on December 31-January 2.
Processed SOHO/EIT 284 image at 19:06 UTC on January 4. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to minor storm on January 5 due to coronal hole effects. Quiet to unsettled is likely on January 6-7. Extremely faint CMEs observed on January 3 and 4 could reach Earth on January 6-8 and cause a few active intervals.
| 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 poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay (presumed) with a weak signal. Of the few stations heard most signals were from Brazil.
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 |
|---|---|---|---|---|---|---|---|
| 10715 | 2004.12.28 | 9 | 5 | N05W19 | 0040 | DSI |
classification was DSO at midnight |
| 10716 | 2004.12.30 | 1 | S13W16 | 0000 | AXX | spotless | |
| Total spot count: | 10 | 5 | |||||
| SSN: | 30 | 15 | |||||
| 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) |
| 2003.11 | 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 | 45.5 (-1.6) |
| 2004.05 | 99.8 | 41.5 | 43.9 (-1.6) |
| 2004.06 | 97.4 | 43.2 | 41.7 (-2.2) |
| 2004.07 | 119.1 | 51.0 | (39.6 predicted, -1.9) |
| 2004.08 | 109.6 | 40.9 | (38.0 predicted, -1.6) |
| 2004.09 | 103.1 | 27.7 | (36.1 predicted, -1.9) |
| 2004.10 | 105.9 | 48.4 | (33.9 predicted, -2.2) |
| 2004.11 | 113.2 | 43.7 | (32.0 predicted, -1.9) |
| 2004.12 | 94.5 | 17.9 | (29.7 predicted, -2.3) |
| 2005.01 | 95.3 (1) | 5.7 (2) | (27.0 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 some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.
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