Last major update issued on January 16, 2012 at 05:25 UTC.
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Annotated geomagnetic activity charts - Carrington rotation 2117 [November-December 2011] - 2118 [December 2011 - January 2012] NEW
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The geomagnetic field was quiet on January 15. Solar wind speed ranged between 326 and 416 km/s. A relatively low speed stream from CH493 arrived at ACE after 15h UTC.
Solar flux measured at 20h UTC on 2.8 GHz was 133.5 (increasing 5.3 over the last solar rotation). The planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.5). Three hour interval K indices: 00000112 (planetary), 01002212 (Boulder).
The background x-ray flux is at the class C1 level.
At midnight UTC the visible solar disk had 13 spotted regions (in 2K resolution SDO images).
Region 11395 [N22W31] decayed slowly and quietly.
Region 11396 [N26W05] lost penumbral area and gained a few spots.
Region 11397 [S19E05] decayed slowly and quietly.
Region 11398 [N13W36] lost many spots and was quiet.
Region 11399 [S23E56] decayed slowly and quietly.
Region 11401 [N17E66] has polarity intermixing and could produce C and minor M class flares. The region displayed significantly less activity than during the previous day.
Region 11402 [N28E67] was mostly quiet and remains capable of producing an M class flare. This region was the source of a very long duration C6.4 event peaking between 04 and 05 UTC on January 16. An associated CME is visible in STEREO-B images.
New region 11403 [S18E28] emerged in the southeast quadrant on January 14 and got an SWPC number the following day.
Spotted regions not reported (or interpreted differently) by NOAA/SWPC:
[S1431] emerged in the northeast quadrant on January 14. Location at midnight: N11E18
[S1432] emerged in the northeast quadrant on January 14. Location at midnight: N13W04
[S1433] emerged in the southwest quadrant on January 14. Location at midnight: S30W53
[S1434] rotated into view at the northeast limb on January 15. Location at midnight: N12E81
[S1435] emerged in the northwest quadrant on January 15. Location at mdnight: N13W15
January 13-15: 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 trans equatorial coronal hole (CH493) was in an Earth facing position on January 12-13. A trans equatorial coronal hole (CH494) could rotate into an Earth facing position on January 17.
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 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 16-17 due to effects from CH493. Quiet conditions are likely on January 18-20 with a chance of unsettled intervals on January 20 due to effects from CH494.
|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:||51||78|
|Sunspot number:||141||208||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||96||122||(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):||85||94||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||132.4 (1)||43.8 (2A) / 90.6 (2B)||(84.4 projected, +5.8)||(4.36)|
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.