Last major update issued on February 26, 2005 at 05:00 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update January 2, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 2, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update January 2, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update February 16, 2005)]
The geomagnetic field was quiet to unsettled on February 25. Solar wind speed ranged between 435 and 581 km/sec under the influence of a moderately high speed stream from CH147.
Solar flux measured at 20h UTC on 2.8 GHz was 78.2. The planetary
index was 9 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 11222332 (planetary), 11233442 (Boulder).
The background x-ray flux is at the class A2 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 10737 decayed slowly and quietly.
Spotted regions not numbered by NOAA/SEC:
[S518] This region emerged in the southeast quadrant on February 25: Location at midnight: S05E59.
February 23-25: No obvious fully or partly Earth directed CMEs were observed.
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 (CH148) was in a geoeffective position on February 23-24.
Processed SOHO/EIT 284 image at 01:06 UTC on February 26. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on February 26-28 due to coronal hole effects.
|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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along long distance north-south paths is fair to poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). WDHP on 1620 and Radio Juventus Don Bosco on 1640 kHz both had fair to good signals. Only a few North American stations were heard, and, as usual, WWZN on 1510 kHz had the best signal (reaching fair levels at best).
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|
|10737||2005.02.23||5||3||S11W59||0030||BXO||area was 0010 at midnight|
|Total spot count:||5||5|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2004.08||109.6||40.9||(38.9 predicted, -1.4)|
|2004.09||103.1||27.7||(36.6 predicted, -2.3)|
|2004.10||105.9||48.4||(34.4 predicted, -2.2)|
|2004.11||113.2||43.7||(32.5 predicted, -1.9)|
|2004.12||94.5||17.9||(30.2 predicted, -2.3)|
|2005.01||102.2||31.3||(27.6 predicted, -2.6)|
|2005.02||99.8 (1)||45.4 (2)||(25.2 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.