Last major update issued on June 3, 2012 at 07:05 UTC.
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[Solar cycles 21-24 (last update
June 2, 2012)]
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[Graphical comparison of cycles 21, 22, 23 and 24 (last
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[Graphical comparison of cycles 10, 12, 13, 14, 16 and
24 (last update June 2, 2012)]
[Historical solar and geomagnetic data charts 1954-2006
(last update April 5, 2007)]
[Archived reports since January 2003 (last update
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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 2. Solar wind speed at SOHO ranged between 326 and 375 km/s. The interplanetary magnetic field swung moderately southwards between 15 and 22:30 UTC causing unsettled to active geomagnetic conditions.
Solar flux measured at 20h UTC on 2.8 GHz was 129.1 (increasing 11.5 over the last solar rotation). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.5). Three hour interval K indices: 11122334 (planetary), 11222323 (Boulder).
The background x-ray flux is at the class B6 level.
At midnight UTC the visible solar disk had 14 spotted active regions (in 2K resolution SDO images).
Region 11490 [S13W65] decayed slowly and quietly.
Region 11492 [S13W37] decayed slowly and quietly.
Region 11493 [N14E36] matured and produced the only interesting event of
the day, a C1.5 flare at 04:31 UTC. This event was associated with a small CME
off the east limb and was visible in both LASCO and STEREO imagery.
Region 11494 [S17E46] was quiet and stable.
Region 11495 [S16W05] decayed slowly and quietly.
Region 11496 [N15E47] developed slowly and quietly.
Region 11497 [S23E22] developed further and could produce at least C
flares.
Region 11498 [N07E57] decayed slowly and quietly.
Spotted active regions not numbered by NOAA/SWPC:
S1696 [S27W70] developed slowly and quietly.
S1703 [N10E38] matured and was quiet. SWPC includes this in AR 11493.
S1704 [N13E61] decayed slowly and quietly.
New region S1705 [S18E70] emerged near the southeast limb with a single
spot.
New region S1706 [N08W07] emerged with a single spot near CH520.
New region S1707 [N16W35] emerged with a tiny spot.
May 31 - June 2: No obviously Earth directed CMEs were observed in LASCO or STEREO imagery.
Coronal hole history (since October
2002)
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) will be 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 active on June 3. Unsettled to minor storm conditions are likely on June 4-6 due to effects from CH520.
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
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.
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 detected |
Spot count | Location at midnight | Area | Classification | SDO / HMI 4K continuum image with magnetic polarity overlay |
Comment | ||||
---|---|---|---|---|---|---|---|---|---|---|---|
SWPC | STAR SDO | SWPC | STAR | Current | Previous | ||||||
2K | 1K | ||||||||||
11490 | 2012.05.23 2012.05.24 |
2 | 3 | 3 | S13W65 | 0070 | DSO | CSO |
|
||
11492 | 2012.05.24 2012.05.25 |
2 | 9 | 4 | S13W37 | 0020 | DSO | DRO |
|
||
S1682 | 2012.05.25 | S22W40 | plage | ||||||||
S1690 | 2012.05.26 | S07W44 | plage | ||||||||
S1691 | 2012.05.26 | S26W51 | plage | ||||||||
11495 | 2012.05.27 2012.05.31 |
5 | 9 | 3 | S14E20 | 0100 | DSO | CRO |
location: S16W05 area: 0020 Hard to make sense of SWPC data for ARs 11494 and 11495. Obvious errors are redlined |
||
S1693 | 2012.05.28 | S20W18 | plage | ||||||||
S1694 | 2012.05.28 | N09W33 | plage | ||||||||
S1696 | 2012.05.29 | 6 | 2 | S27W70 | 0020 | CRO | |||||
11494 | 2012.05.30 2012.05.31 |
3 | 5 | 3 | S14E20 | 0100 | DSO | CSO |
area: 0180 location: S17E46 |
||
11493 | 2012.05.30 2012.05.31 |
8 | 12 | 7 | N15E35 | 0140 | DSO | DSO |
beta-gamma area: 0280 |
||
11496 | 2012.05.30 2012.06.01 |
6 | 11 | 7 | N16E47 | 0100 | DAI | DAI |
|
||
11497 | 2012.05.30 2012.06.01 |
5 | 19 | 10 | S21E21 | 0060 | DSO | DAI |
area: 0250 location: S23E22 |
||
11498 | 2012.05.31 2012.06.01 |
2 | 5 | 3 | N08E55 | 0060 | DSO | CAO | location: N07E57 | ||
S1702 | 2012.05.31 | S27W19 | plage | ||||||||
S1703 | 2012.06.01 | 10 | 6 | N10E38 | 0050 | DRO | |||||
S1704 | 2012.06.01 | 13 | 6 | N13E61 | 0040 | CRO | |||||
S1705 | 2012.06.02 | 1 | 1 | S18E70 | 0010 | HRX | |||||
S1706 | 2012.06.02 | 1 | 1 | N08W07 | 0000 | AXX | |||||
S1707 | 2012.06.02 | 1 | N16W35 | 0000 | AXX | ||||||
Total spot count: | 33 | 105 | 56 | ||||||||
Sunspot number: | 113 | 245 | 186 | (total spot count + 10 * number of spotted regions) | |||||||
Weighted penumbral SN: | 73 | 153 | 104 | (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): | 68 | 86 | 102 | 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 (3) |
---|---|---|---|---|
2008.07 | 65.7 (SF minimum) | 0.5 | 2.8 (-0.4) | |
2008.12 | 69.2 | 0.8 | 1.7 (-) sunspot minimum |
|
2011.03 | 115.0 | 56.2 | 36.9 (+3.5) | 8.18 |
2011.04 | 112.6 | 54.4 | 41.8 (+4.9) | 8.83 |
2011.05 | 95.8 | 41.6 | 47.6 (+5.8) | 8.94 |
2011.06 | 95.8 | 37.0 | 53.2 (+5.6) | 8.06 |
2011.07 | 94.2 | 43.9 | 57.2 (+4.0) | 8.16 |
2011.08 | 101.7 | 50.6 | 59.0 (+1.8) | 7.26 |
2011.09 | 133.8 | 78.0 | 59.5 (+0.5) | 12.27 |
2011.10 | 137.3 | 88.0 | 59.9 (+0.4) | 8.28 |
2011.11 | 153.5 | 96.7 | 61.1 (+1.2) | 5.55 |
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 | 128.9 (1) | 8.8 (2A) / 132.0 (2B) | (73.9 projected, +0.7) | (8.25) |
1) Running average based on the daily 20:00 UTC observed solar flux value at
2800 MHz.
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.