Last major update issued on January 18, 2012 at 06:05 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 to unsettled on January 17. Solar wind speed ranged between 372 and 511 km/s under the decreasing influence of a high speed stream from CH493.
Solar flux measured at 20h UTC on 2.8 GHz was 139.0 (decreasing 5.5 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: 31111111 (planetary), 21122211 (Boulder).
The background x-ray flux is at the class B5 level.
At midnight UTC the visible solar disk had 13 spotted regions (in 2K resolution SDO images).
Region 11396 [N25W32] decayed further and was quiet.
Region 11397 [S18W25] decayed slowly and quietly.
Region 11398 [N12W64] decayed quickly and quietly.
Region 11399 [S23E31] was quiet and stable.
Region 11401 [N17E40] developed further and has polarity intermixing. M class flares are possible. Flares: M1.0/1N at 04:53, C1.4 at 17:19, C2.2 at 18:32 UTC
Region 11402 [N28E42] developed a weak magnetic delta structure in the southeastern part of the largest penumbra. M flares are possible.
Region 11403 [S18E03] developed slowly and quietly.
Region 11405 [N12E55] was quiet and stable.
New region 11406 [S22W56] emerged in the southwest quadrant on January 16 and was assigned an SWPC number the next day.
Spotted regions not reported (or interpreted differently) by NOAA/SWPC:
[S1431] reemerged with spots on January 17. Location at midnight: N10W06
[S1433] emerged in the southwest quadrant on January 14. Location at midnight: S31W82
[S1436] emerged in the northeast quadrant on January 16. Location at mdnight: N17E54
[S1437] emerged in the northeast quadrant on January 16. Location at midnight: N18W05
January 15, 17: 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 poorly defined trans equatorial coronal hole (CH494) was in an Earth facing position on January 16-17. CH494 appears to be closing.
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 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:||62||101|
|Sunspot number:||152||231||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||96||140||(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):||91||104||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||133.2 (1)||52.6 (2A) / 95.9 (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.