Last major update issued on March 13, 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 March 2, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update March 2, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update March 2, 2004)]
[Historical solar and geomagnetic data charts 1954-2003 (last update January 16, 2004)]
[Archived reports (last update March 11, 2004)]
The geomagnetic field was quiet to minor storm on March 12. Solar wind speed ranged between 544 and 750 km/sec under the influence of a high speed stream from coronal hole CH84. Wind speed decreased slowly throughout the day
Solar flux measured at 20h UTC on 2.8 GHz was 107.5. The planetary A
index was 23 (STAR Ap - based on the mean of three hour interval ap indices: 24.0).
Three hour interval K indices: 55433423 (planetary), 45433423 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 3 spotted regions on the visible disk. Solar flare activity was low. A total of 2 C class events was recorded during the day.
Region 10570 decayed quickly in all parts of the region, in particular the trailing spots are disappearing fast. The
leading penumbrae split further and lost much of their area. There is still a magnetic delta structure in the southern elongated
penumbra. A minor M class flare is still possible. Flares: impulsive C3.1 at 02:37 and C1.8 at
New region 10572 emerged in the northeast quadrant on March 11 and was numbered the next day by SEC. Moderately quick development was observed on March 12.
New region 10573 rotated into view at the southeast limb on March 11 and was noticed by SEC the next day.
March 10-12: No partly or fully earth directed CMEs observed. A partial halo CME observed late on March 11 appears to have had a backsided origin.
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 large recurrent trans equatorial coronal hole (CH84) was in a geoeffective position on March 7-11.
Processed SOHO/EIT 284 image at 01:06 UTC on March 13. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on March 13-14 and quiet to unsettled on March 15-17.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor. Propagation along long distance north-south paths is fair to poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela)].
|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|
formerly region S370
classification was DAO
at midnight, area 0090
formerly region S371
classification was HAX
|Total spot count:||31||45|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.09||112.2||48.7||(58.9 predicted, -1.1)|
|2003.10||151.7||65.5||(56.2 predicted, -2.7)|
|2003.11||140.8||67.3||(53.5 predicted, -2.7)|
|2003.12||114.9||46.5||(50.9 predicted, -2.6)|
|2004.01||114.1||37.2||(46.7 predicted, -4.2)|
|2004.02||107.0||46.0||(42.1 predicted, -4.6)|
|2004.03||104.6 (1)||21.6 (2)||(39.7 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.