Last major update issued on January 17, 2012 at 05:10 UTC.
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Annotated geomagnetic activity charts - Carrington rotation 2117 [November-December 2011] - 2118 [December 2011 - January 2012] NEW
[Solar polar fields vs solar cycles - updated June 27, 2011]
The geomagnetic field was quiet to unsettled on January 16. Solar wind speed ranged between 353 and 544 km/s under the influence of a high speed stream from CH493.
Solar flux measured at 20h UTC on 2.8 GHz was 139.7 (increasing 2.3 over the last solar rotation). The planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.0). Three hour interval K indices: 11123232 (planetary), 21124332 (Boulder).
The background x-ray flux is at the class B8 level.
At midnight UTC the visible solar disk had 14 spotted regions (in 2K resolution SDO images).
Region 11395 [N22W42] decayed slowly and quietly. The region could
become spotless today.
Region 11396 [N26W18] decayed significantly and was quiet.
Region 11397 [S19W08] decayed slowly and quietly.
Region 11398 [N13W49] decayed further and was quiet.
Region 11399 [S23E43] was quiet and stable.
Region 11401 [N17E54] has polarity intermixing and could produce M class flares. Flares: C2.5 at 00:18, C3.9 at 08:12, C5.5 long duration event peaking at 10:38 UTC
Region 11402 [N29E55] remains capable of producing an M class flare. Flare: C6.5 very long duration event peaking at 04:44 UTC. This event was associated with a large and wide partial halo CME.
Region 11403 [S18E17] was quiet and stable.
New region 11404 [N13W27] emerged in the northwest quadrant on January 15 and was assigned a number by SWPC one day later.
New region 11405 [N12E67] rotated into view at the northeast limb on January 15 and got an SWPC number the next day.
Spotted regions not reported (or interpreted differently) by NOAA/SWPC:
[S1433] emerged in the southwest quadrant on January 14. Location at midnight: S31W69
[S1436] emerged in the northeast quadrant on January 16. Location at mdnight: N17E68
[S1437] emerged in the northeast quadrant on January 16. Location at midnight: N19E08
[S1438] emerged in the southwest quadrant on January 16. Location at midnight: S21W42
January 14-15: No obviously Earth directed CMEs were observed in LASCO and
January 16: A partial halo CME was observed after an LDE in region 11402 early in the day. While the core of the CME won't reach Earth, there's a chance of a flank impact on January 19.
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 poorly defined trans equatorial coronal hole (CH494) was in an Earth facing position on January 16-17.
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. Propagation on long distance northeast-southwest paths is fair.
The geomagnetic field is expected to be quiet to unsettled on January 17 due to effects from CH493 and quiet on January 18. On January 19 there's a chance of a flank impact from the CME observed on January 16. In that case brief unsettled to active conditions are possible. On January 20-21 weak effects from CH494 are possible.
|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:||40||96|
|Sunspot number:||120||236||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||93||138||(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):||72||106||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||132.9 (1)||47.7 (2A) / 92.4 (2B)||(84.4 projected, +5.8)||(4.59)|
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.