Last major update issued on March 23, 2004 at 04:40 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 unsettled on March 22. Solar wind speed ranged between 395 and 467 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 116.4. The planetary A
index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 11.6).
Three hour interval K indices: 33322333 (planetary), 33322333 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 4 spotted regions on the visible disk. The solar flare activity level was low. A total of 2 C class events was recorded during the day.
Region 10574 developed in the trailing and intermediate spot sections as new negative polarity flux emerged. The
possibility of a minor M class flare has increased. Flare: C8.6 at 06:16 UTC.
Region 10577 was quiet and stable.
Region 10578 developed in the trailing spot section and there is poor separation between the positive and negative polarity areas in the center of the region. There is a fairly good chance of a minor M class flare today or tomorrow. Flare: C1.3 at 02:13 UTC.
New region 10579 was first observed at the southeast limb late on March 19, then became spotless on March 20. Spots reemerged slowly on March 20 and 21.
March 20-22: 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, poorly defined coronal hole (CH85) in the northern hemisphere was in a geoeffective position on March 20. A recurrent coronal hole (CH87) in the northern hemisphere will likely rotate into geoeffective positions on March 25-26.
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 unsettled on March 23 and 25 and quiet to active on March 24 under the influence of a weak high speed stream from coronal hole CH85. A high speed stream from coronal hole CH87 could arrive on March 27 or 28 and cause unsettled to minor storm conditions.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is fair approaching fair to good. Propagation along long distance north-south paths is poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: WLAM Lewiston ME. Stations from the eastern part of North America were heard on many frequencies throughout the MW band].
|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|
classification was EAI
at midnight, area 0170
area was 0070
classification was EAI
at midnight, area 0190
|Total spot count:||47||83|
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||106.9 (1)||45.9 (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.