Last major update issued on March 30, 2004 at 03:45 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 28, 2004)]
The geomagnetic field was quiet to unsettled on March 29. Solar wind speed ranged between 575 and 719 km/sec under the influence of a fairly benign high speed stream from coronal hole CH87.
Solar flux measured at 20h UTC on 2.8 GHz was 128.6. The planetary A
index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 12.5).
Three hour interval K indices: 23333332 (planetary), 14333321 (Boulder).
The background x-ray flux is at the class B5 level.
At midnight there were 3 spotted regions on the visible disk. The solar flare activity level was low. A total of 8 C class events was recorded during the day.
Region 10581 was quiet and stable.
Region 10582 developed new spots with most of the development occurring to the north of the main penumbra. There is a magnetic delta structure in one of the new northern penumbrae and the region has a good chance of producing an M flare. Flares: C2.7 at 13:03, C5.5 at 15:51, C1.5 at 17:35, C3.4 at 18:45, C4.5 at 20:03, C1.1 at 20:36, C1.4 at 21:02 and C8.2/1F at 23:24 UTC.
Region 10587 developed slowly and quietly.
March 27-29: No partly or fully earth directed CMEs observed in limited LASCO data.
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 recurrent coronal hole (CH87) in the northern hemisphere was in a geoeffective position on March 25-27.
Processed SOHO/EIT 284 image at 00:12 UTC on March 18. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on March 30-31 due to a high speed stream from coronal hole CH87. Quiet to unsettled is likely on April 1-2, however, that forecast could quickly change if activity in region 10582 increases.
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 poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). Only a few other TA stations noted with WDHP on 1620 kHz providing the best signal].
|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|
late in the day
late in the day
classification was DAI
at midnight, area 0130
|Total spot count:||99||68|
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||111.2 (1)||74.0 (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.