Last major update issued on July 12, 2006 at 04:00 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update June 7, 2006)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update June 7, 2006)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update June 7, 2006)]
[Historical solar and geomagnetic data charts 1954-2005 (last update March 3, 2006)]
[Archived reports (last update July 9, 2006)]
The geomagnetic field was quiet to unsettled on July 11. Solar wind speed ranged between 345 and 524 km/s (all day average 383 km/s - decreasing 9 km/s from the previous day). A high speed stream from CH231 arrived around noon.
Solar flux measured at 20h UTC on 2.8 GHz was 71.2. The planetary A index
was 7 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 11122233 (planetary), 11223322 (Boulder).
The background x-ray flux is below the class A1 level.
At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10899 was quiet and stable.
July 9-11: No partly or fully Earth directed CMEs were detected in LASCO imagery.
Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A recurrent coronal hole (CH231) in the southern hemisphere was in an Earth facing position on July 7-9.
Processed SOHO/EIT 284 image at 19:06 UTC on July 10. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on July 12 due to a high speed stream from CH231 and mostly quiet July 13-16.
|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. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Radio Cristal del Uruguay again had the best signal. On other frequencies most of the stations heard were from Argentina. Strong signals were noted on 870, 950, 1030 and 1190 kHz. 1610 Radio Guaviyś had fair peaks and was the strongest signal above 1600 kHz. WWZN on 1510 kHz was noted briefly around LSR.
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|
|10899||2006.07.05||3||4||S06W18||0020||BXO||classification was CRO at midnight|
|Total spot count:||3||4|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2006.01||83.4||15.4||(20.7 predicted, -2.3)|
|2006.02||76.5||4.7||(18.2 predicted, -2.5)|
|2006.03||75.4||10.8||(16.4 predicted, -1.8)|
|2006.04||89.0||30.2||(15.7 predicted, -0.7)|
|2006.05||80.9||22.2||(14.9 predicted, -0.8)|
|2006.06||76.5||13.9||(12.7 predicted, -2.2)|
|2006.07||81.1 (1)||11.1 (2)||(11.3 predicted, -1.4)|
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% 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.