Last major update issued on August 24, 2007 at 04:40 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-23 (last update July 23, 2007)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update July 23, 2007)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update July 23, 2007)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports (last update July 1, 2007)]
The geomagnetic field was very quiet on August 23. Solar wind speed ranged between 307 and 351 km/s (average speed was 340 km/s, increasing 1 km/s over the previous day).
Solar flux measured at 20h UTC on 2.8 GHz was 70.8. The planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.5). Three hour interval K indices: 00011001 (planetary), 00011000 (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 10969 was mostly quiet and stable.
August 21-23: No obvious fully or partly Earth directed CMEs were observed in incomplete LASCO imagery.
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 trans equatorial coronal hole (CH287) was in an Earth facing position on August 21-24.
Processed STEREO 195 image at 19:15 UTC on August 23. The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very good. Propagation on long distance northeast-southwest paths is fair.
Monitoring remarks from a location near N58E06: August 22: During two fairly brief nighttime car DX sessions at local beaches I first observed many strong signals from Brazil (audio observed as early as 21:15 UTC on 1330 kHz), Uruguay and Venezuela. 1430 Rádio Clube Paranaense was huge in peaks. 1470 kHz was lively with a mix of several Brazilian stations, Radio Cristal (Uruguay) and Radio Rafaela (Argentina). From 02 UTC until just after LSR I was at another site better suited for DXing North American stations. Signal levels were almost incredible with many stations reaching S9+20dB or +30 dB. In particular stations from Newfoundland and New York were strong, but others from further inland like 760 WJR and 1100 WTAM, had good signals as well.
The geomagnetic field is expected to be quiet on August 24. Quiet to active is likely on August 25-28 due to effects from CH287.
|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.
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|
|Total spot count:||2||2|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2007.02||77.7||10.6||(11.6 predicted, -0.4)|
|2007.03||72.2||4.8||(11.1 predicted, -0.5)|
|2007.04||72.4||3.7||(10.8 predicted, -0.3)|
|2007.05||74.4||11.7||(10.4 predicted, -0.4)|
|2007.06||73.7||12.0||(10.3 predicted, -0.1)|
|2007.07||71.6||10.0||(10.5 predicted, +0.2)|
|2007.08||68.6 (1)||6.5 (2)||(11.0 predicted, +0.5)|
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.