Last major update issued on March 24, 2006 at 05:45 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update March 2, 2006)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update March 2, 2006)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update March 2, 2006)]
[Historical solar and geomagnetic data charts 1954-2005 (last update March 3, 2006)]
[Archived reports (last update March 2, 2006)]
The geomagnetic field was quiet on March 23. Solar wind speed ranged between 366 and 478 (all day average 417) km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 76.6. The planetary A index
was 5 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 22200111 (planetary), 22200111 (Boulder).
The background x-ray flux is at the class A4 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 10862 decayed early in the day. After about 09h UTC some new flux emerged near the inversion line between the opposite polarity areas. The region became more active, however, this development was not sustained until the end of the day and the region is decaying again.
Spotted regions not numbered by NOAA/SEC:
[S635] This region emerged in the southwest quadrant late on March 23. Location at midnight: S04W48
March 21-23: No partly or fully Earth directed CMEs were observed in LASCO imagery.
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 trans equatorial coronal hole (CH217) was in an Earth facing position on March 21-22.
Processed SOHO/EIT 284 image at 01:06 UTC on March 24. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on March 24-26 due to weak effects from CH217.
|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) Effects from a CME are likely to be observed at 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 on long distance northeast-southwest paths is fair to poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Vibración (Venezuela). Propagation was best to Venezuela, Colombia and the Caribbean. RFO Guadaloupe was noted on 640 kHz and several Cuban stations had fair signals. From North America stations frmo Newfoundland and Nova Scotia had the best signals, although none were particularly strong.
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|
|10862||2006.03.18||14||7||S07W66||0060||DAI||classification was CSO at midnight, area 0030|
|Total spot count:||16||10|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2005.09||91.1||21.9||(25.6 predicted, -1.8)|
|2005.10||77.0||8.5||(23.8 predicted, -1.8)|
|2005.11||86.3||18.0||(21.4 predicted, -2.4)|
|2005.12||90.7||41.2||(18.5 predicted, -2.9)|
|2006.01||83.4||15.4||(15.4 predicted, -3.1)|
|2006.02||76.5||4.7||(12.3 predicted, -3.1)|
|2006.03||74.3 (1)||16.0 (2)||(10.1 predicted, -2.2)|
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% lower.
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.