Last major update issued on July 21, 2005 at 03:45 UTC.
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geomagnetic data - last month (updated daily)]
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[Solar cycles 21-23
(last update July 2, 2005)]
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[Graphical comparison
of cycles 21, 22 and 23 (last update July 2, 2005)]
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comparison of cycles 2, 10, 13, 17, 20 and 23 (last update July 2, 2005)]
[Historical solar and
geomagnetic data charts 1954-2004 (last update February 1, 2005)]
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(last update July 19, 2005)]
The geomagnetic field was unsettled to active on July 20. Solar wind speed ranged between 399 and 586 (all day average 504) km/sec under the influence of a high speed stream from CH175.
Solar flux measured at 20h UTC on 2.8 GHz was 72.1. The planetary
A
index was 20 (STAR Ap - based on the mean of three hour interval ap
indices: 20.4).
Three hour interval K indices: 43334334 (planetary), 44434433 (Boulder).
The background x-ray flux is at 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.
July 18-20: No obvious partly or fully 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 well defined recurrent trans equatorial coronal hole (CH175) was in an Earth facing position on July 17-19.
Processed SOHO/EIT 284 image at 01:06 UTC on July 21. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to minor storm on July 21 and quiet to active on July 22 due to a high speed stream from CH175. Quiet to unsettled is likely on July 23-24.
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 unusable. Propagation on long distance north-south paths is poor to very poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay with an unusually poor signal. On other frequencies the best signals were noted from Radio Monte Carlo (Uruguay) on 930 and a Brazilian station on 1130 kHz.
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 |
---|---|---|---|---|---|---|---|
S569 | 2005.07.12 | N06W50 | 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) |
2004.05 | 99.8 | 41.5 | 43.8 (-1.7) |
2004.06 | 97.4 | 43.2 | 41.6 (-2.2) |
2004.07 | 119.1 | 51.1 | 40.2 (-1.4) |
2004.08 | 109.6 | 40.9 | 39.2 (-1.0) |
2004.09 | 103.1 | 27.7 | 37.5 (-1.7) |
2004.10 | 105.9 | 48.0 | 35.9 (-1.6) |
2004.11 | 113.2 | 43.5 | 35.3 (-0.6) |
2004.12 | 94.5 | 17.9 | 35.2 (-0.1) |
2005.01 | 102.2 | 31.3 | (34.6 predicted, -0.6) |
2005.02 | 97.2 | 29.1 | (33.3 predicted, -1.3) |
2005.03 | 89.9 | 24.8 | (31.6 predicted, -1.7) |
2005.04 | 86.0 | 24.4 | (29.7 predicted, -1.9) |
2005.05 | 99.3 | 42.6 | (27.2 predicted, -2.5) |
2005.06 | 93.7 | 39.3 | (25.7 predicted, -1.5) |
2005.07 | 100.4 (1) | 56.5 (2) | (24.7 predicted, -1.0) |
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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