Last major update issued on August 4, 2006 at 04:50 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update July 19, 2006)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update July 19, 2006)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update July 19, 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 August 3. Solar wind speed ranged between 468 and 562 km/s (all day average 535 km/s - decreasing 14 km/s from the previous day) under the slowly decreasing influence of a high speed stream from CH234.
Solar flux measured at 20h UTC on 2.8 GHz was 71.3. The planetary A index
was 6 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 32010122 (planetary), 33121112 (Boulder).
The background x-ray flux is at the class A2 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.
August 1-3: 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 (CH235) in the southern hemisphere (with a trans equatorial extension) was in an Earth facing position on August 2-4.
Processed SOHO/EIT 284 image at 19:06 UTC on August 3. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be mostly quiet on August 4 and most of August 5. A high speed stream from CH235 could arrive during the latter half of August 5 and cause some unsettled and active intervals until August 7.
|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 to good. From North America several stations from Newfoundland, Nova Scotia had good signals, while some of the 50 kW Boston and New York stations also were heard well. Propagation was best to Brazil, Uruguay and Argentina. 920 Novo Tempo (Brazil) was excellent, as was 1410 AM Libre (Uruguay).
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|
|10901||2006.07.22||2||N08W86||0030||BXO||rotated out of view|
|10902||2006.07.30||1||S09W87||0030||AXX||rotated out of view|
|Total spot count:||3||0|
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||72.1 (1)||1.8 (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.