Last major update issued on June 8, 2012 at 04:50 UTC.
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[POES auroral activity level since October
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The geomagnetic field was quiet to unsettled on June 7. Solar wind speed at SOHO ranged between 560 and 722 km/s under the influence of a high speed stream from CH520.
Solar flux measured at 20h UTC on 2.8 GHz was 128.2 (decreasing 8.2 over the last solar rotation). The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.0). Three hour interval K indices: 22222233 (planetary), 22132222 (Boulder).
The background x-ray flux is at the class B7 level.
At midnight UTC the visible solar disk had 9 spotted active regions (in 2K resolution SDO images).
Region 11493 [N15W36] was quiet and stable.
Region 11494 [S16W18] developed slowly with closely spaced opposite polarity spots to th south and southwest of the large penumbra. An M class flare is possible.
Region 11497 [S21W43] lost penumbral area in the largest penumbrae, however, some growth was observed in the southern parts of the region with some polarity intermixing occurring.
Region 11498 [N08E04] decayed slowly and quietly.
Region 11499 [N16E07] decayed losing quite a few small spots. AR 11496 was merged into this region. The region produced the only notable flare of the day, a C9.1/2N at 15:43 UTC.
Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1703 [N13W28] decayed slowly and quietly.
S1713 [N11E19] was quiet and stable.
S1714 [N27W62] developed slowly and quietly.
New region S1715 [S26E67] rotated into view at the southeast limb.
June 5: A filament eruption near AR 11493 and close to the central
meridian was observed beginning at 19:30 UTC. A small CME was observed at 20:39
UTC in STEREO-A.
June 6: A partial halo CME associated with an M2 flare in AR 11494 was observed from 20:39 UTC in LASCO images. This CME could reach Earth late on June 9 or early on June 10.
June 7: No obviously Earth directed CMEs were observed in LASCO or STEREO imagery.
Coronal hole history (since October
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A large recurrent trans equatorial coronal hole (CH520) was in an Earth facing position on June 1-4.
The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, 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 this method, the extent and intensity of both CHs 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 fair.
The geomagnetic field is expected to be quiet to unsettled on June 8 due to effects from CH520. The CME observed on June 6 could reach Earth late on June 9 or early on June 10 and cause unsettled to active conditions with a chance of minor storming.
|Coronal holes (1)||Coronal mass ejection (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 magnetic polarity overlay
merged with AR 11499
|S1703||2012.06.01||15||9||N13W28||0030||CRI||SWPC thinks this is part of AR 11493|
|Total spot count:||38||107||51|
|Sunspot number:||98||197||131||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||68||141||85||(Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)|
|Relative sunspot number (Wolf number):||59||69||72||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 (changed from 0.45 on March 1, 2011) for STAR SDO 2K, k = 0.55 for STAR SDO 1K|
|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)|
|2011.12||141.3||73.0||(64.3 projected, +3.2)||3.78|
|2012.01||132.5||58.3||(68.0 projected, +3.7)||7.15|
|2012.02||106.5||33.1||(71.3 projected, +3.3)||8.81|
|2012.03||114.7||64.2||(73.0 projected, +1.7)||16.08|
|2012.04||113.0||55.2||(73.2 projected, +0.2)||10.10|
|2012.05||121.5||69.0||(73.2 projected, +0.0)||8.75|
|2012.06||130.7 (1)||31.2 (2A) / 133.6(2B)||(73.9 projected, +0.7)||(15.49)|
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 quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international Potsdam WDC 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.