Last major update issued on June 17, 2006 at 04:25 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 June 5, 2006)]
The geomagnetic field was quiet to unsettled on June 16. Solar wind speed ranged between 480 and 696 km/s (all day average 577 km/s - decreasing 4 km/s from the previous day) under the influence of a high speed stream from CH228.
Solar flux measured at 20h UTC on 2.8 GHz was 75.3. The planetary A index
was 10 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 33212233 (planetary), 33312223 (Boulder).
The background x-ray flux is at the class A4 level.
At midnight there were 3 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 1 C class event was recorded during the day from a region well behind the southwest limb. This was a C2.8 flare at 14:23 UTC.
Region 10894 redeveloped spots and was quiet.
Spotted regions not numbered by NOAA/SEC:
[S662] This region emerged in the northeast quadrant on June 15. Slow decay was observed on June 16 and the region could soon become spotless. Location at midnight: N02E23.
[S663] A new region emerged in the southeast quadrant on June 15. The region decayed slowly on June 16 and could become spotless today. Location at midnight: S10E40.
June 14-16: No partly or fully Earth directed CMEs were observed 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 (CH228) in the southern hemisphere was in an Earth facing position on June 12-13.
Processed SOHO/EIT 284 image at 01:06 UTC on June 17. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on June 17. Mostly quiet conditions are likely on June 18-21.
|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. Propagation on long distance northeast-southwest paths is poor to fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Radio Cristal del Uruguay had the best signal tonight. Other TA frequencies had signals mainly from Brazil and 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|
|Total spot count:||0||4|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2005.12||90.7||41.2||(22.8 predicted, -2.1)|
|2006.01||83.4||15.4||(20.1 predicted, -2.7)|
|2006.02||76.5||4.7||(17.1 predicted, -3.0)|
|2006.03||75.4||10.8||(15.1 predicted, -2.0)|
|2006.04||89.0||30.2||(14.4 predicted, -0.7)|
|2006.05||80.9||22.2||(13.5 predicted, -0.9)|
|2006.06||76.8 (1)||14.6 (2)||(11.4 predicted, -2.1)|
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.