Last major update issued on January 28, 2005 at 05:10 UTC.
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The geomagnetic field was inactive to quiet on January 27. Solar wind speed ranged between 332 and 366 km/sec. A weak solar wind disturbance was observed beginning at ACE after 22h UTC, its origin is at this time not obvious.
Solar flux measured at 20h UTC on 2.8 GHz was 86.9. The planetary
A
index was 3 (STAR Ap - based on the mean of three hour interval ap
indices: 3.3).
Three hour interval K indices: 00001211 (planetary), 00111331 (Boulder).
The background x-ray flux is at the class A4 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10723 decayed slowly and was quiet.January 25-27: No obvious fully or partly 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
A coronal hole (CH141) in the southern hemisphere was in a geoeffective position on January 25-26. A recurrent coronal hole in the northern hemisphere (CH142) will be in a geoeffective position on January 27-28.
Processed SOHO/EIT 284 image at 01:06 UTC on January 28. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on January 28 and unsettled to active on January 29-February 1 due to high speed streams from CH141 and CH142. Occasional minor storm intervals are possible.
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 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 with a weak signal. On other frequencies a few stations from North America were noted with the best signals from WWZN on 1510 and KNR (Greenland) on 650 kHz.
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 |
---|---|---|---|---|---|---|---|
10723 | 2005.01.17 | 1 | 1 | N06W57 | 0050 | HSX | area was 0040 at midnight |
10726 | 2005.01.21 | S01W54 | plage | ||||
10727 | 2005.01.24 | 10 | 6 | S09W02 | 0080 | DAO | area was 0050 at midnight |
10728 | 2005.01.25 | 2 | S14E36 | 0010 | BXO | spotless | |
S495 | visible on 2005.01.13 |
S06W87 | plage | ||||
S500 | visible on 2005.01.18 |
N10W47 | plage | ||||
S504 | emerged on 2005.01.24 |
S12W36 | plage | ||||
Total spot count: | 13 | 7 | |||||
SSN: | 43 | 27 |
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 | 104.7 (1) | 46.8 (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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