Last major update issued on March 11, 2011 at 05:35 UTC.
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Annotated geomagnetic activity charts - Carrington rotation 2105 [Dec-Jan.2011] - 2106 [Jan.-Feb.2011]
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The geomagnetic field was quiet to minor storm on March 10. A solar wind shock was observed at SOHO at 05:45 UTC. While the increase in solar wind speed was unimpressive and the total IMF field was low to moderate, the IMF has been southwards since the arrival of the CME.
Solar flux measured at 20h UTC on 2.8 GHz was 131.3 (increasing 40.1 over the last solar rotation). The planetary A index was 20 (STAR Ap - based on the mean of three hour interval ap indices: 19.5). Three hour interval K indices: 22443245 (planetary), 22433233 (Boulder).
The background x-ray flux is at the class B8 level.
At midnight UTC the visible solar disk had 9 spotted regions.
Region 11166 has several small magnetic delta structures in the large
central penumbra and one delta in the southeastern trailing penumbra. Another
major flare is possible. Flares: C2.9 at 03:58, C6.2 at 07:12, C4.2 at
13:25, C4.7 at 13:46, C2.0 at 14:24 UTC.
Region 11167 was quiet and stable.
Region 11169 decayed in the trailing spot section while development was
observed in the leading spot section, there is only minor polarity intermixing.
Region 11170 rotated partly out of view at the southwest limb.
Region 11171 was quiet and stable.
Region S891 behind the southwest limb was the likely source of a C4.0 flare at 19:07 and an M1.1 flare at 22:41 UTC. The flares were observed at the southwest limb, however, there is a slight chance AR 11170 might have been involved.
Spotted regions not numbered by NOAA/SWPC:
[S896] A tiny spot reemerged on March 10. Location at midnight:
N16W34
[S900] Tiny spots emerged in an old plage area in the southeastern
quadrant on March 8, a single tiny spot was still vsisible on March 10. Location at midnight:
S18W02.
[S902] A few spots emerged in the northeast quadrant on March 10.
Location at midnight: N19E37
[S903] This region began to rotate into view late on March 10. Location
at midnight: N11E85
March 8-10: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
Coronal hole history (since late October
2002)
Compare today's report to the situation one solar rotation ago:
28 days ago
27 days
ago 26
days ago
An extension (CH439) of the southern polar coronal hole was Earth facing on March 10.
The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is very poor. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to minor storm on March 11 and quiet to unsettled on March 12 due to CME effects. On March 13-14 quiet to unsettled conditions are possible as a stream from CH439 dominates the solar wind.
| 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
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 polarity overlay |
Comment | |||
|---|---|---|---|---|---|---|---|---|---|---|
| SWPC | STAR SDO | SWPC | STAR | Current | Previous | |||||
| 11166 | 2011.03.02 | 25 | 55 | N09W26 | 0750 | EKC | EKC |
 |
 |
beta-gamma-delta |
| 11167 | 2011.03.02 2011.03.03 |
2 | 2 | N12W66 | 0010 | BXO | BXO |
 |
 |
location: N12W63 |
| 11169 | 2011.03.05 2011.03.06 |
15 | 33 | N20E18 | 0220 | ESC | ESI |
 |
 |
beta-gamma |
| S895 | 2011.03.05 | N07W53 | plage | |||||||
| S896 | 2011.03.06 | 1 | N16W34 | 0000 | AXX |
 |
||||
| 11170 | 2011.03.07 2011.03.08 |
6 | 2 | S25W94 | 0020 | HRX | BXO |
 |
 |
location: S26W86 |
| S898 | 2011.03.07 | S13E11 | plage | |||||||
| S899 | 2011.03.07 | N19W30 | plage | |||||||
| 11171 | 2011.03.08 | 6 | S19E41 | 0000 | BXO |
 |
 |
location of spots: S20E30 | ||
| S900 | 2011.03.08 | 1 | S18W02 | 0000 | AXX |
 |
 |
|||
| S901 | 2011.03.08 | S22W40 | plage | |||||||
| S902 | 2011.03.10 | 3 | N19E37 | 0010 | BXO |
 |
||||
| S903 | 2011.03.10 | 1 | N11E85 | 0000 | AXX |
 |
||||
| Total spot count: | 48 | 104 | ||||||||
| Sunspot number: | 88 | 194 | ||||||||
| 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 |
3.25 |
| 2009.12 | 76.7 | 10.8 | 8.3 (+0.7) | 1.41 / 1.92 |
| 2010.01 | 81.1 | 13.2 | 9.3 (+1.0) | 2.93 / 3.07 |
| 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 | 16.8 (+0.4) | 6.31 / 5.15 |
| 2010.08 | 79.2 | 19.6 | 17.4 (+0.6) | 8.49 / 7.77 |
| 2010.09 | 81.1 | 25.2 | (19.1 predicted, +1.7) | 5.33 / 5.45 |
| 2010.10 | 81.6 | 23.5 | (21.7 predicted, +2.6) | 6.07 / 6.27 |
| 2010.11 | 82.5 | 21.6 | (24.5 predicted, +2.8) | 4.80 / 5.50 |
| 2010.12 | 84.2 | 14.5 | (26.9 predicted, +2.4) | 3.41 / 4.35 |
| 2011.01 | 83.6 | 19.1 | (29.0 predicted, +2.1) | 4.32 |
| 2011.02 | 94.6 | 29.4 | (31.1 predicted, +2.1) | 5.41 |
| 2011.03 | 132.5 (1) | 33.6 (2A) / 104.1 (2B) | (33.0 predicted, +1.9) | (11.91) |
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 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.
