Last major update issued on February 21, 2004 at 05:05 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 on February 20. Solar wind speed ranged between 345 and 443 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 95.4. The planetary A
index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 5.6).
Three hour interval K indices: 11112121 (planetary), 11112322 (Boulder).
The background x-ray flux is at the class A8 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 10561 was quiet and stable.
Region 10562 decayed slightly and was quiet.
New region 10563 rotated into view at the southeast limb on February 19 and was numbered the next day by SEC. Slow development was observed on February 20.
Spotted regions not numbered by NOAA/SEC:
[S361] This region emerged in hot plage in the northeast quadrant on February 20. The region is complex with a negative polarity field partly overlaying the leading positive polarity field. If the region continues to develop a magnetic delta structure could soon form. Location at midnight: N15E54.
February 18-20: 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 parts of a coronal hole (CH82) in the northern hemisphere will rotate into geoeffective positions on February 22-23. A coronal hole (CH83) is currently rotating into view at the east limb.
Processed SOHO/EIT 284 image at 01:06 UTC on February 21. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be mostly quiet to unsettled until February 24. On February 25-26 a high speed from coronal hole CH82 could arrive and may cause unsettled to active conditions.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor at night and fair during the morning openings. Propagation along long distance north-south paths is poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Vibración (Venezuela) on the northwesterly EWE and on a new longwire pointed westsouthwest. That longwire had excellent signals from WDHP on 1620 and WGIT (Puerto Rico) on 1660 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
|Location at midnight||Area||Classification||Comment|
area was 0020
classification was CSO
at midnight, area 0030
formerly region S360
classification was HAX
at midnight, area 0040,
|Total spot count:||4||13|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|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||105.2 (1)||49.7 (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.