Last major update issued on January 7, 2012 at 07:50 UTC.
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Annotated geomagnetic activity charts - Carrington rotation 2116 [October-November 2011] - 2117 [November-December 2011]
[Solar polar fields vs solar cycles - updated June 27, 2011]
The geomagnetic field was quiet on January 6. Solar wind speed ranged between 417 and 479 km/s, weakly under the influence of a high speed coronal hole stream.
Solar flux measured at 20h UTC on 2.8 GHz was 135.5 (decreasing 4.5 over the last solar rotation). The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.5). Three hour interval K indices: 11011222 (planetary), 11021322 (Boulder).
The background x-ray flux is at the class B6 level.
At midnight UTC the visible solar disk had 10 spotted regions (in 2K resolution SDO images).
Region 11388 [S24W60] was quiet and stable.
Region 11389 [S18W48] became a reversed polarity region again with negative polarity spots appearing ahead of the large penumbra. Note that SWPC includes region S1401 in this region. Flare: C1.4 at 06:08 UTC.
Region 11391 [N13E27] developed slowly and was mostly quiet. A weak magnetic delta structure could be forming to the north of the leader spot.
Region 11392 [N20W33] added several spots and could produce further C class flares. Flares: C2.2 at 11:25, C2.6 at 00:09 (on Jan.7) UTC.
Region 11393 [N17W15] developed significantly and could produce C flares.
New region 11394 [N18E43] emerged in the northeast quadrant on January 5 and got an SWPC number the next day.
Spotted regions not reported (or interpreted differently) by NOAA/SWPC:
[S1401] rotated into view at the southeast limb on December 28 and developed significantly in the central and trailing spot sections on Dec.29-31. The leading spot section decayed on January 1. Quick decay was observed on January 2-4. Location at midnight: S24W43.
[S1411] emerged in the southeast quadrant on January 6. Location at midnight: S17E63
[S1412] emerged in the southwest quadrant on January 6. Location at midnight: S18W61
[S1413] emerged in the northeast quadrant on January 6. Location at midnight: N33E20
January 4 and 6: No obviously Earth directed CMEs were observed in LASCO and
January 5: A fairly large filament eruption to the north of region 11392 was recorded as a long duration C2.1 long duration event peaking at 12:38 UTC. While the core of the associated CME will not reach Earth, STEREO imagery hints at the possibility that the outer edge of the CME could do so.
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 recurrent trans equatorial coronal hole (CH491) was in an Earth facing position on January 4-5.
The above coronal hole map is based on a new method where coronal holes are detected automatically. The method may need some fine tuning, however, 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 the new method, the extent and intensity of both holes 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 to fair. Propagation on long distance northeast-southwest paths is fair.
The geomagnetic field is expected to be quiet to unsettled on January 7-8 due to weak effects from CH491. There's a minor chance of a weak flank CME impact on January 8 or 9.
|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
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
SWPC includes region S1401
rotated out of view
|Total spot count:||48||87|
|Sunspot number:||118||187||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||81||126||(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):||71||84||k * (sunspot number). k = 0.6 for SWPC. k = 0.45 (changed from 0.33 on Nov.1) for STAR SDO|
|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)|
|2010.10||81.6||23.5||23.2 (+3.6)||6.07 / 6.27|
|2010.11||82.5||21.5||26.5 (+3.3)||4.80 / 5.50|
|2010.12||84.2||14.4||28.8 (+2.3)||3.41 / 4.35|
|2011.01||83.6||19.1||31.0 (+2.2)||4.32 / 5.51|
|2011.02||94.6||29.4||33.4 (+2.4)||5.41 / 6.44|
|2011.03||115.0||56.2||36.9 (+3.5)||7.79 / 8.18|
|2011.04||112.6||54.4||41.8 (+4.9)||9.71 / 8.83|
|2011.05||95.8||41.6||47.6 (+5.8)||9.18 / 8.94|
|2011.06||95.8||37.0||53.2 (+5.6)||8.96 / 8.06|
|2011.07||94.2||43.9||(57.8 projected, +4.6)||9.14 / 8.16|
|2011.08||101.7||50.6||(62.0 projected, +4.2)||8.16 / 7.26|
|2011.09||133.8||78.0||(65.3 projected, +3.3)||12.80 / 12.27|
|2011.10||137.3||88.0||(68.8 projected, +3.5)||7.52|
|2011.11||153.5||96.7||(73.2 projected, +4.3)||4.58|
|2011.12||141.3||73.0||(78.6 projected, +5.5)||3.32|
|2012.01||135.4 (1)||17.6 (2A) / 91.0 (2B)||(84.4 projected, +5.8)||(4.60)|
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 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.