Last major update issued on January 13, 2012 at 05:05 UTC.
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The geomagnetic field was quiet on January 12. Solar wind speed ranged between 376 and 505 km/s. A high speed stream associated with CH492 arrived at ACE near 17h UTC.
Solar flux measured at 20h UTC on 2.8 GHz was 116.8 (decreasing 4.2 over the last solar rotation). The planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.6). Three hour interval K indices: 20012222 (planetary), 21022212 (Boulder).
The background x-ray flux is at the class B6 level.
At midnight UTC the visible solar disk had 7 spotted regions (in 2K resolution SDO images).
Region 11391 [N12W53] decayed in the trailing spot section while quick
development was observed in the southeastern part of the leading spot section. A
magnetic delta structure has formed and the region could produce a minor M class
Region 11395 [N22E08] decayed slowly and was mostly quiet. Flare: C1.5 at 00:58 UTC
New region 11396 [N26E33] emerged in the northeast quadrant on January 9, was spotless the next day, then reemerged on January 11 with SWPC assigning its number the following day.
Spotted regions not reported (or interpreted differently) by NOAA/SWPC:
[S1424] rotated into view at the southeast limb on January 11. Location at midnight: S16E60
[S1425] emerged in the northeast quadrant on January 11. Location at midnight: N14E04
[S1426] emerged in the southeast quadrant on January 12. Location at midnight: S20E42
[S1427] emerged in the southeast quadrant on January 12. Location at midnight: S24E34
A region just behind the northeast limb produced a very long duration C2.5 event peaking at 10:01 UTC. This event was associated with a large and wide CME.
A reversed polarity region with a spot slightly too small to be counted was located at S37W54 at midnight.
January 10-12: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
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 coronal hole (CH492) in the southern hemisphere was in an Earth facing position on January 9-10. A recurrent trans equatorial coronal hole (CH493) was in an Earth facing position on January 12.
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 poor to fair.
The geomagnetic field is expected to be quiet to unsettled on January 13 due to weak effects from CH492. Quiet conditions are likely on January 14 becoming quiet to unsettled on January 15-16 due to effects from CH493.
|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
|Total spot count:||15||43|
|Sunspot number:||45||113||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||25||59||(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):||27||51||k * (sunspot number). k = 0.6 for SWPC. k = 0.45 (changed from 0.33 on Nov.1, 2011) 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||133.1(1)||31.9 (2A) / 82.5 (2B)||(84.4 projected, +5.8)||(4.47)|
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.