Last major update issued on August 17, 2005 at 04:40 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update August 2, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update August 2, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update August 2, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update August 13, 2005)]
The geomagnetic field was unsettled to active on August 16. Solar wind speed ranged between 354 and 799 (all day average 622) km/sec under the influence of a high speed stream from CH181.
Solar flux measured at 20h UTC on 2.8 GHz was 75.8. The planetary
index was 19 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 34443333 (planetary), 34243323 (Boulder).
The background x-ray flux is at the class A4 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10797 decayed further and lost both spots and penumbral area.
Region 10798 added a small leader spot and was quiet.
August 14-16: No obvious partly or fully Earth directed CMEs were observed.
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
Recurrent trans equatorial coronal hole (CH181) was in an Earth facing position on August 13-15. A recurrent coronal hole (CH182) in the southern hemisphere will be in an Earth facing position on August 17-18. While this coronal hole didn't produce any disturbance during the previous rotation, it has extended somewhat in a northerly direction.
Processed SOHO/EIT 284 image at 01:06 UTC on August 17. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on August 17 and quiet to unsettled on August 18-19. Some effects from CH182 are possible starting late on August 20 and on August 21, possibly resulting in unsettled to active conditions.
|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 poor to very poor. Propagation on long distance northeast-southwest paths is poor to fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay at first, later both Radio Vibración and CPN Radio (Perú) were observed. From North America only a few stations were audible, WWZN on 1510 kHz and Canadian stations on 590, 620, 710, 780 and 930 kHz. Propagation was less auroral than expected with Colombia noted on 870 and 980 kHz and several Venezuelan stations including 1430 Radio Bahía present. A few stations from Argentina were noted after LSR with 710 Radio Diez and 950 Radio Belgrano at fair signals levels. Surprisingly few stations from Brazil were audible, however, 1540 Rádio Baixa Verde had good peaks around 02:30 UTC.
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|
|10797||2005.08.11||25||13||S14W10||0130||DSI||classification was DAO at midnight|
|Total spot count:||28||15|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2005.02||97.2||29.2||(33.5 predicted, -1.1)|
|2005.03||89.9||24.5||(32.1 predicted, -1.4)|
|2005.04||86.0||24.4||(30.2 predicted, -1.9)|
|2005.05||99.3||42.6||(27.6 predicted, -2.6)|
|2005.06||93.7||39.6||(26.1 predicted, -1.5)|
|2005.07||96.4||39.9||(25.1 predicted, -1.0)|
|2005.08||88.8 (1)||31.7 (2)||(23.2 predicted, -1.9)|
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.