Last major update issued on August 9, 2006 at 04:45 UTC.
geomagnetic data - last month (updated daily)]
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[Solar cycles 21-23 (last update August 6, 2006)]
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[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update August 6, 2006)]
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The geomagnetic field was quiet to active on August 8. Solar wind speed ranged between 549 and 627 km/s (all day average 578 km/s - increasing 51 km/s over the previous day) under the influence of a high speed stream from CH235.
Solar flux measured at 20h UTC on 2.8 GHz was 71.4. The planetary A index
was 12 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 23433221 (planetary), 23332221 (Boulder).
The background x-ray flux is at the class A4 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.
New region 10903 emerged on August 7 near the southeast limb and was numbered the next day by NOAA/SEC. Slow development was observed on August 8.
August 6-8: 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
No obvious coronal holes are currently in or approaching Earth facing positions.
Processed SOHO/EIT 284 image at 01:06 UTC on August 9. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on August 9-10 and quiet on August 11-13.
|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 very poor. Only a few weak signals from Newfoundland were detected in addition to 1510 WWZN. Propagation on long distance northeast-southwest paths is very good, particularly to Argentina and Uruguay. 580 Radio Clarín was heard way better than I've ever heard them. At times there was some interference from Argentina. Even on a very difficult frequency like 1340 kHz (because of heavy splatter from 1341 BBC) there was a discernable signal, probably from Uruguay. 1690 Radio Apocalipsis II had very good peaks.
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|
|10903||2006.08.07||2||3||S09E56||0040||CRO||formerly region S670
classification was CSO at midnight
|Total spot count:||2||3|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2006.02||76.5||4.7||(18.4 predicted, -2.4)|
|2006.03||75.4||10.8||(16.6 predicted, -1.8)|
|2006.04||89.0||30.2||(15.9 predicted, -0.7)|
|2006.05||80.9||22.2||(15.1 predicted, -0.8)|
|2006.06||76.5||13.9||(12.9 predicted, -2.2)|
|2006.07||75.7||12.2||(11.4 predicted, -1.5)|
|2006.08||70.8 (1)||2.2 (2)||(11.4 predicted, -0.0)|
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.