Last update issued on March 25, 2003 at 03:45 UTC.
[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update March 3, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update March 3, 2003)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update March 3, 2003)]
[Historical solar and geomagnetic data charts 1954-2002 (last update January 27, 2003)]
[Archived reports (last update March 24, 2003)]
The geomagnetic field was quiet to active on March 24. Solar wind speed ranged between 461 and 642 km/sec, generally decreasing all day as a high speed stream ended.
Solar flux measured at 20h UTC on 2.8 GHz was 97.8. The planetary A
index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.0).
Three hour interval K indices: 32432222 (planetary), 22331111 (Boulder).
The background x-ray flux is at the class B1-B2 level.
At midnight there were 6 spotted regions on the visible disk, 2 of the regions have not yet been numbered by SEC/NOAA. Solar flare activity was low. A total of 2 C class events was recorded during the day.
Region 10318 developed slowly and quietly.
Region 10319 developed several new spots and was quiet.
New region 10320 emerged in the northeast quadrant near the center of the visible disk.
New region 10321 rotated into view at the northeast limb. Flares: C2.0 at 04:31 and C1.2 at 13:17 UTC.
Spotted regions not yet numbered by SEC/NOAA:
[S126] A new region emerged in the southwest quadrant, near the location of spotless region 10316. Location at midnight: S08W08.
[S127] A new region emerged in the southwest quadrant, south southwest of region S126. Location at midnight: S17W11.
March 22-24: No obviously geoeffective 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
A well placed, developing and recurrent coronal hole (CH26) mainly in the northern hemisphere was in a geoeffective position on March 22-23. A coronal hole (CH27) in the southern hemisphere will rotate into a geoeffective position on March 24-27.
Processed SOHO EIT 284 image at 01:06 UTC on March 25. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to minor storm on March 25-26 due to a high speed stream from coronal hole CH26. Quiet to active is likely on March 27-31 due to another high speed stream, this time from CH27. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor, propagation along north-south paths is fair to poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay, then Radio Vibración (Venezuela) after 02h UTC]
|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.
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 SEC/NOAA. 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.
|Solar region||Date numbered||SEC
|Location at midnight||Area||Classification||Comment|
classification was CSO
at midnight, area 0020
area was 0090
|Total spot count:||24||22|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2002.09||175.8||109.6||(94.7 predicted, -4.0)|
|2002.10||167.0||97.5||(91.2 predicted, -3.5)|
|2002.11||168.7||95.0||(86.0 predicted, -5.2)|
|2002.12||157.2||81.6||(81.6 predicted, -4.4)|
|2003.01||144.0||79.5||(78.6 predicted, -3.0)|
|2003.02||124.5||46.2||(73.6 predicted, -5.0)|
|2003.03||128.8 (1)||85.5 (2)||(67.9 predicted, -5.7)|
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 (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% less.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.