Last major update issued on May 11, 2012 at 05:05 UTC.
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Annotated geomagnetic activity charts - Carrington rotation
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[Solar polar fields vs solar cycles - updated
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The geomagnetic field was quiet to active on May 10. Solar wind speed at SOHO ranged between 557 and 603 km/s under the influence of a high speed stream from CH515.
Solar flux measured at 20h UTC on 2.8 GHz was 130.7 (increasing 33.0 over the last solar rotation). The Potsdam WDC planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 15.3). Three hour interval K indices: 33322234 (planetary), 33222233 (Boulder).
The background x-ray flux is at the class B7 level.
At midnight UTC the visible solar disk had 8 spotted active regions (in 2K resolution SDO images).
Region 11474 [N17W33] was quiet and stable.
Region 11476 [N12E08] has a very complex magnetic delta structure in the
southern part of the huge penumbra (spanning about 6 degrees latitudinally and
longitudinally). There are several layers of opposite polarities in the most
complex parts. The region has the potential to produce an X5+ flare.
Flares: M5.7/2B at 04:18, C7.9 at 05:10, C8.3
at 05:22, M1.7 at 20:26 UTC and numerous sub C5 level flares.
Region 11477 [S22E47] added a few spots and was quiet.
New region 11478 [S24E56] rotated into view at the southeast limb on May
8 and was numbered by SWPC two days later.
Spotted active regions not numbered by NOAA/SWPC:
S1636 [S16E04] was quiet and stable.
S1642 [S15E26] developed slowly and quietly.
New region S1644 [N14E81] rotated into view at the northeast limb with a
single penumbra.
New region S1645 [S12E22] was split off from S1642.
May 8: A filament eruption beginning at 09:45 UTC near AR 11474 across
the central meridian was the source of a small CME observed in both STEREO-A and
B imagery after 11h UTC. While most of the ejected material was over the
northern limbs, it appears that a part of the CME is Earth directed.
May 9-10: No obviously Earth directed significant CMEs were observed in 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 recurrent trans equatorial coronal hole (CH515) was in an Earth facing position on May 5-7. A southern hemisphere coronal hole (CH516) was Earth facing on May 9-10.
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 active on May 11 due to a high speed stream from CH515. The CME observed on May 8 could reach Earth on May 11. Starting late on May 12 or early on May 13 a high speed stream from CH516 could cause quiet to active conditions until May 14.
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 | ||||||||||
11471 | 2012.04.27 2012.04.28 |
1 | S22W91 | 0090 | HSX |
rotated out of view |
|||||
11474 | 2012.05.01 2012.05.02 |
2 | 1 | N16W38 | 0000 | AXX | location: N17W33 | ||||
11475 | 2012.05.02 | N05W34 | plage | ||||||||
11476 | 2012.05.04 2012.05.05 |
50 | 130 | 64 | N12E08 | 1040 | FKC | FKC |
beta-gamma-delta area: 1800 location: N10E06 |
||
S1629 | 2012.05.04 | S16W52 | plage | ||||||||
S1631 | 2012.05.04 | S24W25 | plage | ||||||||
S1633 | 2012.05.06 | N12W14 | plage | ||||||||
11477 | 2012.05.07 2012.05.08 |
1 | 5 | 2 | S22E47 | 0100 | HSX | HAX | |||
11478 | 2012.05.08 2012.05.10 |
1 | 3 | 1 | S24E55 | 0090 | HSX | HSX | |||
S1636 | 2012.05.08 | 4 | 3 | S16E04 | 0010 | BXO | |||||
S1637 | 2012.05.08 | N23W29 | plage | ||||||||
S1638 | 2012.05.08 | S19W33 | plage | ||||||||
S1639 | 2012.05.08 | S16W44 | plage | ||||||||
S1640 | 2012.05.08 | S16W61 | plage | ||||||||
S1641 | 2012.05.08 | N11W53 | plage | ||||||||
S1642 | 2012.05.09 | 8 | 2 | S15E26 | 0010 | CRO | |||||
S1643 | 2012.05.09 | S14W56 | plage | ||||||||
S1644 | 2012.05.10 | 1 | 1 | N14E81 | 0070 | HSX | |||||
S1645 | 2012.05.10 | 5 | 3 | S12E22 | 0010 | BXO | |||||
Total spot count: | 53 | 158 | 77 | ||||||||
Sunspot number: | 93 | 238 | 157 | (total spot count + 10 * number of spotted regions) | |||||||
Weighted penumbral SN: | 88 | 186 | 105 | (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): | 56 | 83 | 86 | 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 |
|
2011.02 | 94.6 | 29.4 | 33.4 (+2.4) | 6.44 |
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 | (61.2 projected, +1.3) | 5.55 |
2011.12 | 141.3 | 73.0 | (63.9 projected, +2.7) | 3.78 |
2012.01 | 132.5 | 58.3 | (67.4 projected, +3.5) | 7.15 |
2012.02 | 106.5 | 33.1 | (71.4 projected, +4.0) | 8.81 |
2012.03 | 114.7 | 64.2 | (73.5 projected, +2.1) | 16.08 |
2012.04 | 113.0 | 55.2 | (74.5 projected, +1.0) | 10.10 |
2012.05 | 118.9 (1) | 30.6 (2A) / 94.9 (2B) | (75.8 projected, +1.3) | (10.06) |
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.