Last major update issued on February 5, 2004 at 04:35 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 4. Solar wind speed ranged between 500 and 638 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 101.4. The planetary A
index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 15.3).
Three hour interval K indices: 32334333 (planetary), 41333222 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 5 spotted regions on the visible disk. Solar flare activity was low. A total of 1 C class event was recorded during the day.
Region 10547 lost some small spots while the single penumbra developed slowly. Flare:
impulsive C9.9/1F at 11:18 UTC.
Region 10549 decayed slowly and quietly.
Region 10551 developed moderately quickly and has mixed polarities. A minor M class flare is possible.
Region 10552 developed slowly and quietly.
Spotted regions not numbered by NOAA/SEC:
[S347] This region first emerged in the southeast quadrant on February 3, then was spotless for several hours on February
before reemerging during the latter half of the day with several spots. Location at midnight: S05E13.
February 2-4: 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 was in a geoeffective position on January 28 - February 2.
Processed SOHO/EIT 284 image at 19:06 UTC on February 4. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on February 5 under the influence of a high speed stream from coronal hole CH78 and quiet to unsettled on February 6-9.
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, Radio Vibración (Venezuela) was noted at times. Several stations from New York and Boston were observed 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 |
|---|---|---|---|---|---|---|---|
| 10546 | 2004.01.29 | S12W11 | plage | ||||
| 10547 | 2004.01.30 | 6 | 2 | S08W55 | 0060 | DAO |
classification was HAX at midnight |
| 10548 | 2004.01.31 | N06W22 | plage | ||||
| 10549 | 2004.01.31 | 14 | 17 | N14E17 | 0200 | EAO |
area was 0110 at midnight |
| 10550 | 2004.02.02 | 2 | S09W39 | 0020 | CAO | spotless | |
| 10551 | 2004.02.02 | 8 | 23 | S06E39 | 0110 | DAO |
beta-gamma classification was DAI at midnight, area 0170 location S06E37 |
| 10552 | 2004.02.02 | 5 | 5 | S08W06 | 0050 | CSO |
classification was DSO at midnight, location S08W08 |
| S337 | emerged on 2004.01.26 |
S04W73 | plage | ||||
| S338 | emerged on 2004.01.27 |
N16W86 | plage | ||||
| S343 | emerged on 2004.01.31 |
N15W22 | plage | ||||
| S347 | emerged on 2004.02.03 |
7 | S05E13 | 0040 | DSO |
classification was CRO at 20:48 UTC, region developed further late in the day |
|
| Total spot count: | 35 | 54 | |||||
| SSN: | 85 | 104 | |||||
| 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 | 99.9 (1) | 12.1 (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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