Last major update issued on February 21, 2006 at 05:00 UTC.
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The geomagnetic field was quiet to major storm on February 20. Solar wind speed ranged between 392 and 644 (all day average 571) km/sec under the influence of a high speed stream from CH212.
Solar flux measured at 20h UTC on 2.8 GHz was 76.2. The
planetary A index was 20 (STAR Ap - based on the mean of three hour interval ap
indices: 20.1).
Three hour interval K indices: 22344622 (planetary), 12344522 (Boulder).
The background x-ray flux is below the class A1 level.
At midnight the visible solar disk was spotless. The solar flare activity level was very low. No C class events were recorded during the day.
February 18-20: 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 coronal hole (CH212) in the northern hemisphere was in an Earth facing position on February 17-18. A small, poorly defined, coronal hole (CH213) in the southern hemisphere was in an Earth facing position on February 20.
Processed SOHO/EIT 284 image at 01:06 UTC on February 21. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on February 21-24 due to coronal hole effects, isolated active intervals are possible on February 21.
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 to fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). Only a few stations from North America were audible, mainly the most common stations from Newfoundland and Nova Scotia. The path to the southern part of South America was open again with stations on 1030 and 1070 kHz (both Argentina) having the best signals.
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 spot count |
STAR spot count |
Location at midnight | Area | Classification | Comment |
---|---|---|---|---|---|---|---|
10854 | 2006.02.15 | S08W48 | plage | ||||
10855 | 2006.02.16 | N05W24 | plage | ||||
S623 | 2006.02.13 | S12W29 | plage | ||||
S626 | 2006.02.18 | N02W36 | plage | ||||
Total spot count: | 0 | 0 | |||||
SSN: | 0 | 0 |
Month | Average solar flux at Earth |
International sunspot number | Smoothed sunspot number |
---|---|---|---|
2000.04 | 184.2 | 125.5 | 120.8 cycle 23 sunspot max. |
2000.07 | 202.3 | 170.1 | 119.8 |
2001.12 | 235.1 | 132.2 | 114.6 (-0.9) |
2004.12 | 94.5 | 17.9 | 35.2 (-0.1) |
2005.01 | 102.2 | 31.3 | 34.6 (-0.6) |
2005.02 | 97.2 | 29.2 | 33.9 (-0.7) |
2005.03 | 89.9 | 24.5 | 33.5 (-0.4) |
2005.04 | 86.0 | 24.4 | 31.6 (-1.9) |
2005.05 | 99.3 | 42.6 | 28.9 (-2.7) |
2005.06 | 93.7 | 39.6 | 28.8 (-0.1) |
2005.07 | 96.4 | 39.9 | 29.1 (+0.3) |
2005.08 | 90.5 | 36.4 | (27.6 predicted, -1.5) |
2005.09 | 91.1 | 22.1 | (25.8 predicted, -1.8) |
2005.10 | 77.0 | 8.5 | (24.0 predicted, -1.8) |
2005.11 | 86.3 | 18.0 | (21.6 predicted, -2.4) |
2005.12 | 90.7 | 41.2 | (18.7 predicted, -2.9) |
2006.01 | 83.4 | 15.4 | (15.6 predicted, -3.1) |
2006.02 | 76.7 (1) | 4.0 (2) | (12.5 predicted, -3.1) |
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.
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