Last major update issued on February 6, 2004 at 04:15 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 3, 2004)]
The geomagnetic field was quiet to active on February 5. Solar wind speed ranged between 474 and 609 km/sec under the influence of a high speed stream from coronal hole CH78.
Solar flux measured at 20h UTC on 2.8 GHz was 105.5. The planetary A
index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.3).
Three hour interval K indices: 33343332 (planetary), 43431333 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 4 spotted regions on the visible disk. Solar flare activity was low. A total of 2 C class events was recorded during the day.
Region 10547 decayed quickly late in the day and became spotless early on February 6. Flare:
C1.5 at 07:54 UTC.
Region 10549 developed slowly with new small spots emerging. Flare: C1.3 at 06:36 UTC.
Region 10551 developed further and may be capable of producing a minor M class flare.
Region 10552 had spots most of the day, however, the region decayed quickly during the evening and had lost all spots by midnight.
New region 10553 emerged in the southeast quadrant on February 3 and was numbered by SEC two days later. The region was
decaying slowly late in the day.
February 3-5: 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
No obvious coronal holes are currently in or near geoeffective positions.
Processed SOHO/EIT 284 image at 13:06 UTC on February 5. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled February 6-10.
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 poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay with a weak signal, Radio Vibración (Venezuela) was noted at times. WDHP on 1620 kHz had a fairly good signal. On the northwesterly EWE I observed a large number of carriers].
| 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 |
|---|---|---|---|---|---|---|---|
| 10546 | 2004.01.29 | S12W24 | plage | ||||
| 10547 | 2004.01.30 | 2 | 1 | S08W70 | 0040 | HSX |
classification was HRX at midnight, area 0020 |
| 10548 | 2004.01.31 | N06W35 | plage | ||||
| 10549 | 2004.01.31 | 26 | 27 | N14E04 | 0120 | EAO |
classification was EAI at midnight |
| 10550 | 2004.02.02 | S09W52 | plage | ||||
| 10551 | 2004.02.02 | 21 | 25 | S06E26 | 0220 | DKO |
classification was DKI at midnight, area 0350 location S07E24 |
| 10552 | 2004.02.02 | 6 | S08W20 | 0030 | DAO | spotless at midnight | |
| 10553 | 2004.02.05 | 4 | 4 | S05E01 | 0030 | DSO | formerly region S347 |
| S337 | emerged on 2004.01.26 |
S04W86 | plage | ||||
| S343 | emerged on 2004.01.31 |
N15W35 | plage | ||||
| Total spot count: | 59 | 57 | |||||
| SSN: | 109 | 97 | |||||
| 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 | 65.6 | (54.9 predicted, -2.7) |
| 2003.11 | 140.8 | 67.2 | (52.2 predicted, -2.7) |
| 2003.12 | 114.9 | 47.0 | (49.6 predicted, -2.6) |
| 2004.01 | 114.1 | 37.2 | (45.4 predicted, -4.2) |
| 2004.02 | 101.0 (1) | 15.9 (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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