Last major update issued on June 18, 2011 at 06:05 UTC.
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[POES auroral activity level charts since October
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Annotated geomagnetic activity charts - Carrington rotation 2109 [April-May 2011] - 2110 [May-June 2011] NEW
[Solar polar fields vs solar cycles - updated June 11, 2011]
The geomagnetic field was quiet to active on June 17. Solar wind speed ranged between 408 and 559 km/s. A minor solar wind shock was observed at 02:04 UTC at SOHO, the arrival of the CME observed on June 14.
Solar flux measured at 20h UTC on 2.8 GHz was 104.3 (increasing 20.7over the last solar rotation). The planetary A index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 11.0). Three hour interval K indices: 43113322 (planetary), 33223322 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight UTC the visible solar disk had 6 spotted regions.
Region 11234 has minor polarity intermixing. Decay was observed in the
eastern and western spot section while some development occurred in the central
spot section. Flares: C1.1 at 22:10, C1.4 at
23:13 and C3.9 at 23:42 UTC.
Region 11236 decayed in the trailing spot section while quite a few tiny spots emerged in the southern negative polarity area.
New region 11237 rotated into view at the southeast limb on June 16 and was numbered by NOAA/SWPC the next day.
Spotted regions not numbered by NOAA/SWPC:
[S1057] reemerged with a small spot on June 17. Location at midnight: S18W62
[S1064] emerged in the southeast quadrant on June 13. Location at midnight: S16W04
[S1070] emerged in the northeast quadrant on June 17. Location at midnight: N17E55
June 15-17: No obviously earth directed CMEs were observed.
Coronal hole history (since late October
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 (CH457) will likely become Earth facing on June 20-21. A coronal hole (CH458) in the southern hemisphere was Earth facing on June 16 and may be too far to the south to cause a disturbance, CH458 has lost some of its area over the last few days.
The above coronal hole map is based on a new method where coronal holes are detected automatically. The method may need some fine tuning, however, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using the new method, the extent and intensity of both holes are consistent with other data sources.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to unsettled on June 18. There's a chance of a few unsettled and active intervals on June 19-20 if a stream from CH458 reaches Earth. Otherwise quiet conditions are likely.
|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
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.
(Click on image for higher resolution image) Compare to the previous day's image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) is positive.
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
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with polarity overlay
|1||1||S14E66||0000||AXX||formerly region S1069|
|Total spot count:||35||79|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
|2008.07||65.7 (SF minimum)||0.5||2.8 (-0.4)|
|2010.02||84.7||18.8||10.6 (+1.3)||4.15 / 4.61|
|2010.03||83.4||15.4||12.3 (+1.7)||4.58 / 4.65|
|2010.04||75.9||8.0||14.0 (+1.7)||10.22 / 10.24|
|2010.05||73.8||8.7||15.5 (+1.5)||9.18 / 8.15|
|2010.06||72.5||13.6||16.4 (+0.9)||8.17 / 6.85|
|2010.07||79.8||16.1||16.7 (+0.3)||6.31 / 5.15|
|2010.08||79.2||19.6||17.4 (+0.7)||8.49 / 7.77|
|2010.09||81.1||25.2||19.6 (+2.2)||5.33 / 5.45|
|2010.10||81.6||23.5||23.2 (+3.6)||6.07 / 6.27|
|2010.11||82.5||21.5||26.5 (+3.3)||4.80 / 5.50|
|2010.12||84.2||14.4||(29.4 predicted, +2.9)||3.41 / 4.35|
|2011.01||83.6||19.1||(32.6 predicted, +3.2)||4.32 / 5.51|
|2011.02||94.6||29.4||(35.2 predicted, +2.6)||5.41 / 6.44|
|2011.03||115.0||56.2||(37.5 predicted, +2.3)||7.79|
|2011.04||112.6||54.4||(40.4 predicted, +2.9)||9.71|
|2011.05||95.8||41.6||(43.7 predicted, +3.3)||9.18|
|2011.06||97.8 (1)||36.1 (2A) / 63.6 (2B)||(47.4 predicted, +3.7)||(10.17)|
1) Running average based on the daily 20:00 UTC observed solar flux value at
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official SIDC international sunspot number is typically 30-50% lower. 2B) Month average to date.
3) Running average based on the preliminary 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 on analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.
SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.