Last major update issued on June 21, 2010 at 04:25 UTC.
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The geomagnetic field was quiet on June 20. Solar wind speed ranged between 347 and 415 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 70.0. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.4). Three hour interval K indices: 10011112 (planetary), 11012112 (Boulder).
The background x-ray flux is at the class A5 level.
At midnight there was 1 spotted region on the visible solar disk.
Region 11082 became spotless. Unfortunately NOAA/SWPC at the time of writing has a mistake in their SRS report as region S781 has mistakenly been merged with region 11082.
Spotted regions not numbered by NOAA/SWPC:
[S781] This region emerged quickly near the central meridian late on June 19 and just southwest of region 11082, slow developement was observed on June 20. Location at midnight: N26W11.
June 17-19: No obviously Earth directed CMEs were seen in LASCO or STEREO images.
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 small and poorly defined coronal hole (CH409) in the northern hemisphere was in an Earth facing position on June 19. A recurrent trans equatorial coronal hole (CH410) will likely rotate into an Earth facing position on June 22-24.
Processed SOHO/EIT 195 image at 00:00 UTC on June 21. The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet on June 21 and 24-25. On June 22 and 23 there's a chance of a few unsettled intervals should effects from CH409 reach Earth. On June 26-28 a high speed stream from CH410 could cause quiet 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) 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/SWPC. 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 SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.
|Active region||Date numbered||SWPC
|Location at midnight||Area||SWPC
|11082||2010.06.17||3||N27W05||0030||DSO||spotless, SWPC has merged this region with S781
actual location: N29W03
|Total spot count:||3||2|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
cycle 23 sunspot max.
|2008.07||65.7 (SF minimum)||0.5||2.8 (-0.4)|
|2009.07||68.2||3.2||3.6 (+0.9)||5.49 / 4.55|
|2009.08||67.3||0.0||4.8 (+1.2)||5.70 / 4.89|
|2009.09||70.5||4.3||6.1 (+1.3)||3.88 / 3.61|
|2009.10||72.6||4.8||7.0 (+0.9)||3.66 / 3.56|
|2009.11||73.6||4.1||7.6 (+0.6)||2.45 / 2.63|
|2009.12||76.7||10.8||(8.2 predicted, +0.6)||1.41 / 1.92|
|2010.01||81.1||13.1||(9.2 predicted, +1.0)||2.93 / 3.07|
|2010.02||84.7||18.6||(10.7 predicted, +1.5)||4.15 / 4.61|
|2010.03||83.4||15.4||(12.5 predicted, +1.8)||4.58 / 4.65|
|2010.04||75.9||7.9||(14.1 predicted, +1.6)||10.22 / 10.24|
|2010.05||73.8||8.8||(15.4 predicted, +1.3)||9.18 / 8.15|
|2010.06||71.9 (1)||13.8 (2)||(16.9 predicted, +1.5)||(7.45)|
1) Running average based on the
daily 20:00 UTC observed solar flux
value at 2800 MHz.
2) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official international sunspot number is typically 30-50% lower.
3) Running average based on the daily SWPC ap indices. Values in red are based on the official NGDC ap indices.
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.