Last major update issued on February 25, 2004 at 04:25 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update February 2, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update February 2, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update February
2, 2004)]
[Historical solar and geomagnetic data charts 1954-2003 (last update January 16,
2004)]
[Archived reports (last update February 18, 2004)]
The geomagnetic field was quiet to unsettled on February 24. Solar wind speed ranged between 350 and 440 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 105.5. The planetary A
index was 11 (STAR Ap - based on the mean of three hour interval ap indices:
11.9).
Three hour interval K indices: 33333322 (planetary), 33332222 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 3 spotted regions on the visible disk. Solar flare activity was very low. No C class events was recorded during the day.
Region 10563 was quiet and stable.
Region 10564 developed fairly quickly and is a large compact region with
M class flare potential. There may be a weak magnetic delta structure in the
rapidly expanding trailing penumbra.
Region 10565 developed in the leading penumbra, however, slow decay was
observed elsewhere.
February 22-24: 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
The southernmost part of a coronal hole (CH82) in the northern hemisphere was in a geoeffective position on February 22-23. A recurrent trans equatorial coronal hole (CH83) will rotate into a geoeffective position on February 26-28.
Processed SOHO/EIT 284 image at 01:06 UTC on February 24. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on February 25-26 and quiet to unsettled on February 27-28. On February 29 - March 2 a high speed stream from coronal hole CH83 will likely cause unsettled to minor storm conditions.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is fair. Propagation along long distance north-south paths is poor to fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). On other frequencies strong signals were noted from Nova Scotia, Newfoundland, New York and Boston stations. Propagation to Brazil was better than it has been for quite a few days, Rádio Uirapuru, Fortaleza on 760 kHz had a particularly good signal].
| 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 |
|---|---|---|---|---|---|---|---|
| 10560 | 2004.02.15 | S17W87 | plage | ||||
| 10561 | 2004.02.15 | N02W56 | plage | ||||
| 10562 | 2004.02.19 | S13E00 | plage | ||||
| 10563 | 2004.02.20 | 2 | 2 | S24E13 | 0030 | HSX | |
| 10564 | 2004.02.21 | 27 | 53 | N15E00 | 0470 | EKI |
beta-gamma classification was EKC at midnight, area 0700 |
| 10565 | 2004.02.23 | 13 | 18 | S04E22 | 0120 | CAO |
classification was DAI at midnight |
| 10566 | 2004.02.24 | 3 | N05E21 | 0020 | CRO |
formerly region S363 spotless |
|
| S358 | emerged on 2004.02.18 |
S06W40 | plage | ||||
| S359 | emerged on 2004.02.18 |
S14W38 | plage | ||||
| Total spot count: | 45 | 73 | |||||
| SSN: | 85 | 103 | |||||
| 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) |
| 2003.01 | 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 | 61.8 (-3.2) |
| 2003.08 | 122.1 | 72.7 | (59.4 predicted, -2.4) |
| 2003.09 | 112.2 | 48.7 | (57.6 predicted, -1.8) |
| 2003.10 | 151.7 | 65.5 | (54.9 predicted, -2.7) |
| 2003.11 | 140.8 | 67.3 | (52.2 predicted, -2.7) |
| 2003.12 | 114.9 | 46.5 | (49.6 predicted, -2.6) |
| 2004.01 | 114.1 | 37.2 | (45.4 predicted, -4.2) |
| 2004.02 | 104.8 (1) | 58.8 (2) | (40.8 predicted, -4.6) |
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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