Last major update issued on March 7, 2006 at 04:15 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 inactive to unsettled on March 6. Solar wind speed ranged between 276 and 415 (all day average 328) km/sec, increasingly under the influence of a recurrent disturbance. This disturbance was observed 4 weeks ago and has an unknown source. It is associated with a fairly low speed and unusually high density solar wind.
Solar flux measured at 20h UTC on 2.8 GHz was 73.6. The planetary A index
was 8 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 00113333 (planetary), 00113333 (Boulder).
The background x-ray flux is below the class A1 level.
There were 3 very small 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 10856 reemerged with a few very small spots.
Region 10857 had a single small spot.
Spotted regions not numbered by NOAA/SEC:
[S629] This region has been observed as a small area of plage over the last few days and developed a small spot early on March 6. Location at midnight: S15E16.
March 4-6: No obviously fully or partly Earth directed CMEs were 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 recurrent trans equatorial coronal hole (CH215) appears to have become larger over the last solar rotation and was in an Earth facing position on March 5-7.
Processed SOHO/EIT 284 image at 01:20 UTC on February 28. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on March 7-11, first under the influence of the current disturbance, then due to effects from CH215.
|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 to very poor. Propagation on long distance northeast-southwest paths is poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela) with a weak signal. Only a few stations from North America were audible with the best signal from 930 CJYQ.
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|
|10856||2006.02.27||4||2||S10W25||0010||AXX||area was 0000 at midnight|
|Total spot count:||7||4|
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||75.2 (1)||2.2 (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.