Last major update issued on February 21, 2005 at 03:35 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update January 2, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 2, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update January 2, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update February 16, 2005)]
The geomagnetic field was quiet to active on February 20. Solar wind speed ranged between 427 and 552 km/sec, generally decreasing all day.
Solar flux measured at 20h UTC on 2.8 GHz was 95.7. The planetary
index was 12 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 43312322 (planetary), 12343333 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.Region 10735 decayed slowly and quietly.
February 18-20: No obvious fully or partly Earth directed CMEs were observed.
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 small coronal hole (CH147) in the northern hemisphere was in a geoeffective position on February 19-20. A recurrent coronal hole (CH148) in the northern hemisphere will likely rotate to a geoeffective position on February 23-24.
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 quiet to unsettled on February 21. For February 22-23 a low speed stream from CH147 could cause some unsettled and active intervals.
|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.
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. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela) with a fair to good signal. On other frequencies only a few stations from North America were heard, CJYQ on 930 kHz had a fair signal. Propagation to Colombia was better than in a long time with stations on 610 and 770 kHz having fair signals.
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|
|10733||2005.02.07||1||S08W93||0070||HSX||rotated out of view|
|10735||2005.02.10||12||5||S09W58||0440||DKO||area was 0300 at midnight|
formerly region S517
classification was CAO at midnight, area 0050
|Total spot count:||20||11|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2004.08||109.6||40.9||(38.9 predicted, -1.4)|
|2004.09||103.1||27.7||(36.6 predicted, -2.3)|
|2004.10||105.9||48.4||(34.4 predicted, -2.2)|
|2004.11||113.2||43.7||(32.5 predicted, -1.9)|
|2004.12||94.5||17.9||(30.2 predicted, -2.3)|
|2005.01||102.2||31.3||(27.6 predicted, -2.6)|
|2005.02||103.2 (1)||40.3 (2)||(25.2 predicted, -2.4)|
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 some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.