Last major update issued on February 19, 2004 at 04:20 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 18. Solar wind speed ranged between 381 and 538 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 97.7. The planetary A
index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 9.3).
Three hour interval K indices: 22122332 (planetary), 12212333 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 4 spotted regions on the visible disk. Solar flare activity was very low. No C class events was recorded during the day.
Region 10554 decayed slowly and quietly. The region will rotate out of view at the southwest limb late today and
early tomorrow.
Region 10561 was quiet and stable.
Spotted regions not numbered by NOAA/SEC:
[S358] This region emerged in the southeast quadrant on February 18. Location at midnight: S06E25.
[S359] A new region emerged south of region S358 late on February 18. Location at midnight: S14E27.
February 16-18: 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
There is a small coronal hole (CH81) in the southern hemisphere. CH81 was in a geoeffective position on February 17.
Processed SOHO/EIT 284 image at 01:06 UTC on February 19. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on February 19 and 21. On February 20 there is a possibility of a weak high speed stream arriving from coronal hole CH81, this could cause unsettled to active conditions during parts of that day.
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 fair to good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Rafaela (Argentina). At times interference was noted from a few stations from Brazil. On the northwesterly EWE several stations from Newfoundland, Nova Scotia and the northern part of South America could be heard with the best propagation on frequencies below 1200 kHz].
| 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 |
|---|---|---|---|---|---|---|---|
| 10554 | 2004.02.07 | 1 | 1 | S08W69 | 0060 | HSX | |
| 10555 | 2004.02.09 | S16W48 | plage | ||||
| 10556 | 2004.02.11 | N17W71 (SEC: N15W80) |
plage SEC has moved region 10556 to the position of region S354 |
||||
| 10558 | 2004.02.13 | S16W32 | plage | ||||
| 10560 | 2004.02.15 | S17W09 | plage | ||||
| 10561 | 2004.02.15 | 2 | 1 | N02E26 | 0020 | HSX | |
| S354 | emerged on 2004.02.14 |
N16W81 | plage | ||||
| S357 | emerged on 2004.02.17 |
N10W38 | plage | ||||
| S358 | emerged on 2004.02.18 |
2 | S06E25 | 0010 | AXX | ||
| S359 | emerged on 2004.02.18 |
1 | S14E27 | 0000 | AXX | ||
| Total spot count: | 3 | 5 | |||||
| SSN: | 23 | 45 | |||||
| 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 | 106.2 (1) | 47.4 (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.
| [DX-Listeners' Club] |