Last major update issued on June 7, 2012 at 05:10 UTC.
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[POES auroral activity level since October
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[Solar polar fields vs solar cycles - updated June 27, 2011]
The geomagnetic field was quiet to active on June 6. Solar wind speed at SOHO ranged between 590 and 775 km/s under the influence of a high speed stream from CH520.
Solar flux measured at 18h UTC on 2.8 GHz was 132.7 (increasing 2.0 over the last solar rotation, the measurement at 20h UTC was flare enhanced). The Potsdam WDC planetary A index was 19 (STAR Ap - based on the mean of three hour interval ap indices: 18.8). Three hour interval K indices: 44233343 (planetary), 34233443 (Boulder).
The background x-ray flux is at the class B6 level.
At midnight UTC the visible solar disk had 13 spotted active regions (in 2K resolution SDO images).
Region 11492 [S14W83] developed as it rotated to the west limb.
Region 11493 [N15W22] was quiet and stable.
Region 11494 [S16W05] developed early in the day, however, the magnetic delta structure disappeared after the M class event. Flare: M2.1/1B at 20:06 UTC. This event was associated with both type II and IV radio sweeps. A CME was observed in both LASCO and STEREO imagery. While most of the ejected material has a southward direction, parts of the CME appear to be heading towards earth.
Region 11496 [N17W08] decayed slowly and quietly.
Region 11497 [S21W31] decayed slowly and quietly.
Region 11498 [N08E04] developed in the northern part and decayed in the southern section.
Region 11499 [N16E07] developed slightly with an increase in polarity intermixing due to the negative polarity area emerging centrally in the eastern half of this extensive region.
Region 11502 [S16E13] was quiet and stable.
Region 11503 [N10W55] decayed slowly and quietly.
Spotted active regions not numbered by NOAA/SWPC:
S1703 [N13W14] lost penumbral area and remained quiet.
S1709 [N13E37] was quiet and stable.
S1711 [S19W86] was quiet and stable.
New region S1713 [N11E34] emerged with a single spot.
New region S1714 [N27W49] emerged near the northern limit of CH520.
June 4: No obviously Earth directed CMEs were observed in LASCO or STEREO
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 on June 9.
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 good.
The geomagnetic field is expected to be quiet to unsettled on June 7-8 due to effects from CH520, occasional active intervals are possible. There's a slight chance of weak effects from the CME observed on June 5 late on June 8 or early on June 9. The CME observed on June 6 could reach Earth on June 9 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
note that SWPC data is for AR S1711 as they lost track of AR 11492
|S1703||2012.06.01||20||8||N13W14||0070||DRI||SWPC thinks this is part of AR 11493|
|Total spot count:||51||157||75|
|Sunspot number:||131||287||205||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||76||199||117||(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):||79||100||113||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||131.1 (1)||27.9 (2A) / 139.5 (2B)||(73.9 projected, +0.7)||(16.56)|
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.