Last major update issued on January 31, 2004 at 05:35 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update January 4, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 4, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update January
4, 2004)]
[Historical solar and geomagnetic data charts 1954-2003 (last update January 16,
2004)]
[Archived reports (last update January 27, 2004)]
The geomagnetic field was quiet to minor storm on January 30. Solar wind speed ranged between 399 and 852 km/sec, mainly under the influence of a high speed stream from coronal hole CH78.
Solar flux measured at 20h UTC on 2.8 GHz was 92.7. The planetary A
index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 17.9).
Three hour interval K indices: 23354333 (planetary), 23354332 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 5 spotted regions on the visible disk. Solar flare activity was low. A total of 4 C class events was recorded during the day.
Region 10545 decayed slowly and quietly.
Region 10546 was quiet and stable.
New region 10547 emerged in the southeast quadrant on January 29 and was numbered by SEC the next day. The region developed
several small spots on January 30 and has polarity intermixing.
Spotted regions not numbered by NOAA/SEC:
[S341] This region emerged in the northeast quadrant on January 30. Location at midnight: N06E43.
[S342] An interesting region rotated partly into view at the northeast limb on January 30. Location at midnight: N13E78. Flares:
C1.4 at 11:52, C1.1 at 12:25, C2.1 at 16:08 and C1.1 at 21:07 UTC.
January 28-30: No partly or fully earth directed CME 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 (CH78) in the northern hemisphere will rotate into a geoeffective position on January 28 - February 2. Another coronal hole (CH79) in the southern hemisphere is the southern part of what was coronal hole CH74 during the previous rotation.
Processed SOHO/EIT 284 image at 01:06 UTC on January 31. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to minor storm on January 31 and unsettled to minor storm on February 1-5 under the influence of high speed streams from coronal holes CH78 and CH79. Occasional major storm intervals are possible.
Long distance low 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 good to very good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay with a strong signal. A large number of stations from southern Brazil and Argentina were noted on other frequencies.]
| 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 |
|---|---|---|---|---|---|---|---|
| 10545 | 2004.01.29 | 5 | 4 | S20W32 | 0040 | DSO |
classification was CSO at midnight, area 0020 |
| 10546 | 2004.01.29 | 3 | 4 | S11E55 | 0050 | CSO |
location was S12E53 at midnight |
| 10547 | 2004.01.39 | 4 | 9 | S09E14 | 0030 | CSO |
formerly region S340 beta-gamma |
| S336 | emerged on 2004.01.26 |
N12W44 | plage | ||||
| S337 | emerged on 2004.01.26 |
S04W08 | plage | ||||
| S338 | emerged on 2004.01.27 |
N16W21 | plage | ||||
| S341 | emerged on 2004.01.30 |
2 | N06E43 | 0020 | CSO | ||
| S342 | visible on 2004.01.30 |
4 | N13E78 | 0030 | CAO | ||
| Total spot count: | 12 | 23 | |||||
| SSN: | 42 | 73 | |||||
| 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) |
| 2002.12 | 157.2 | 80.8 | 82.0 (-3.2) |
| 2003.01 | 144.0 | 79.7 | 80.8 (-1.2) |
| 2003.02 | 124.5 | 46.0 | 78.3 (-2.5) |
| 2003.03 | 131.4 | 61.1 | 74.0 (-4.3) |
| 2003.04 | 126.4 | 60.0 | 70.1 (-3.9) |
| 2003.05 | 115.7 | 55.2 | 67.6 (-2.5) |
| 2003.06 | 129.3 | 77.4 | 65.0 (-2.6) |
| 2003.07 | 127.7 | 83.3 | (62.0 predicted, -3.0) |
| 2003.08 | 122.1 | 72.7 | (59.4 predicted, -2.6) |
| 2003.09 | 112.2 | 48.7 | (57.5 predicted, -1.9) |
| 2003.10 | 151.7 | 65.6 | (54.7 predicted, -2.8) |
| 2003.11 | 140.8 | 67.2 | (52.0 predicted, -2.7) |
| 2003.12 | 114.9 | 47.0 | (49.4 predicted, -2.6) |
| 2004.01 | 114.8 (1) | 59.8 (2) | (45.3 predicted, -4.1) |
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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