Last major update issued on November 28, 2011 at 03:45 UTC.
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Annotated geomagnetic activity charts - Carrington rotation 2114 [August-September 2011] - 2115 [September-October 2011]
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The geomagnetic field was quiet to unsettled on November 27. Solar wind speed ranged between 343 and 453 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 135.2 (decreasing 2.9 over the last solar rotation). The planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.6). Three hour interval K indices: 11311211 (planetary), 11322220 (Boulder).
The background x-ray flux is at the class B5 level.
At midnight UTC the visible solar disk had 9 spotted regions (in 2K resolution SDO images).
Region 11352 [S23W79] decayed slowly and rotated to the southwest limb.
Region 11353 [N10W61] decayed slowly and quietly.
Region 11355 [N15W33] decayed slowly and quietly.
Region 11356 [N17W24] decayed slowly and was mostly quiet. Flare: C1.4 at 11:02 UTC (this event may have been associated with a filament eruption to the southeast of the region)
Region 11358 [N21E13] lost some trailing spots and gained a few spots in the central part. Flare: C1.1 at 12:03 UTC
Region 11360 [N17W10] decayed slowly and quietly.
Region 11361 [N20E36] developed significantly and could produce C flares.
New region 11362 [N07E78] rotated into view at the northeast limb.
Spotted regions not reported by NOAA/SWPC:
[S1338] emerged in the northeast quadrant on November 26. Location at midnight: N17E46
November 25: No obviously Earth directed CMEs observed.
November 26: A filament eruption across the solar equator stretching from northwest of region 11354 to the northwest of region 11353 was observed beginning at 05:58 UTC on Nov.26 and was the source of a long duration C1.2 event peaking at 07:10. This event was associated with a significant increase in proton fluxes and a large full halo CME. While Earth does not appear to be in the path of the core CME, a flank impact is very likely.
November 27: A filament eruption near the center of the visible disk was observed beginning at 11:12 UTC. A small CME was observed soon afterwards in STEREO-A images.
Coronal hole history (since late October
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A coronal hole (CH486) in the southern hemisphere was in an Earth facing position on November 26-27.
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. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be initially quiet on November 28. During the latter half of the day or early on Nov.29 the CME observed on Nov.26 is expected to arrive and could cause unsettled to minor storm conditions. A coronal hole related disturbance could start on November 29 and last until December 1 with occasional unsettled and active intervals.
|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:||43||65|
|Sunspot number:||123||155||(total spot count + 10 * number of spotted regions)|
|Classification adjusted SN:||79||90||(Sum of total spot count + classification adjustment for each AR. Classification adjustment: X=0, R=3, A/S=5, H/K=10)|
|Relative sunspot number (Wolf number):||74||70||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)|
|2010.07||79.8||16.1||16.7 (+0.3)||6.31 / 5.15|
|2010.08||79.2||19.6||17.4 (+0.7)||8.49 / 7.77|
|2010.09||81.1||25.2||19.6 (+2.2)||5.33 / 5.45|
|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||(47.4 predicted, +5.6)||9.18 / 8.94|
|2011.06||95.8||37.0||(52.5 predicted, +5.1)||8.96 / 8.06|
|2011.07||94.2||43.9||(58.2 predicted, +5.7)||9.14 / 8.16|
|2011.08||101.7||50.6||(63.7 predicted, +5.5)||8.16 / 7.26|
|2011.09||133.8||78.0||(67.0 predicted, +3.3)||12.80 / 12.27|
|2011.10||137.3||88.0||(70.5 predicted, +3.5)||7.52|
|2011.11||154.9 (1)||122.4 (2A) / 136.0 (2B)||(74.9 predicted, +4.4)||(4.24)|
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.