Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 28, 2012 at 05:40 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update November 1, 2012)] [Cycle 24 progress (last update November 1, 2012) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update November 1, 2012)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update November 1, 2012)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update November 4, 2012)]

[POES auroral activity level since October 2009 - updated October 7, 2012]
[Solar polar fields vs solar cycles - updated November 27, 2012]

Recent activity

The geomagnetic field was very quiet on November 27. Solar wind speed at SOHO ranged between 389 and 608 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 117.1 (increasing 12.9 over the last solar rotation). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.1). Three hour interval K indices: 11111011 (planetary), 11112211 (Boulder).

The background x-ray flux was at the class B3 level.

At midnight UTC the visible solar disk had 10 spotted active regions (in 2K resolution SDO images).

Region 11618 [N08W80] decayed further and produced the largest flare of the day, an M1.6 event at 15:57 UTC, as it rotated to the northwest limb.
Region 11620 [S12W42] extended longitudinally and still has a fairly weak magnetic delta structure in a central penumbra. Another M class flare is possible. Flares >C5: C5.9 at 02:15, M1.0 at 21:26, C7.1 at 23:24 UTC.
Region 11621 [N15E38] was quiet and developed slowly. There's weak polarity intermixing in the southeastern section.
Region 11622 [S23E03] decayed and could soon become spotless.
New region 11623 [N08E78] rotated into view with a large leader spot.

Spotted regions not numbered by NOAA/SWPC:
S2072 [S15E13] was quiet and stable.
S2073 [S10W07] was quiet and stable.
New region S2079 [S17E28] emerged with a tiny spot.
New region S2080 [N22E23] emerged with a few spots.
New region S2081 [N00W02] emerged as a trans equatorial region with northern hemisphere polarity layout.

Coronal mass ejections (CMEs)

November 25-26: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
November 27: Several interesting events were observed during the day. A filament eruption near AR 11621 began just after midnight and was later on associated with a partial halo CME in LASCO imagery. There's a chance this CME could reach Earth on November 30. A very slow filament eruption across the equator and mostly in the western hemisphere was observed during the morning. STEREO imagery indicate weak components of the associated CME could be Earth directed. Another filament eruption was observed beginning at 20:45 UTC between AR 11621 and AR S2080. The associated CME could have Earth directed components.

Coronal holes

Coronal hole history (since October 2002)
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 (CH546) was in an Earth facing position on November 27.

Coronal hole map

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 fair. Propagation on long distance northeast-southwest paths is poor.


The geomagnetic field is expected to be quiet on November 28-29. A high speed stream from CH546 could cause quiet to active conditions on November 30 and December 1. Several CMEs could reach Earth these days as well and could cause occasional minor storm intervals.

Coronal holes (1) Coronal mass ejection (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 green.
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.

Active solar regions

Click on image for higher resolution image) Compare to the previous day's image. 0.5k 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
2K 1K
11618 2012.11.15
10 3 2 N09W81 0170 EAO BXO

area: 0020

11620 2012.11.18
22 48 22 S12W43 0260 EKC EKC beta-gamma-delta

area: 0650

S2064 2012.11.19       S21W32           plage
S2067 2012.11.21       S17W52           plage
11622 2012.11.23
  1   S24E02 0000   AXX  
S2071 2012.11.23       S20W34           plage
11621 2012.11.24 2 6 5 N16E37 0130 CAO CSO beta-gamma

area: 0200

S2072 2012.11.24   1   S15E13 0000   AXX  
S2073 2012.11.24   1 1 S10W07 0000   AXX  
S2074 2012.11.24       N15W30           plage
S2075 2012.11.24       S05W44           plage
11623 2012.11.26
2 3 3 N11E74 0170 DSO DHO location: N08E78

area: 0450

S2077 2012.11.26       S40W02         plage
S2078 2012.11.26       N11E20         plage
S2079 2012.11.27   1 1 S17E28 0000   AXX    
S2080 2012.11.27   3 2 N22E23 0010   BXO    
S2081 2012.11.27   2   N00W02 0000   BXO    
Total spot count: 36 69 36  
Sunspot number: 76 169 106  (total spot count + 10 * number of spotted regions)
Weighted SN: 61 94 61  (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): 46 59 58 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
2011.09 133.8 78.0 59.5 (+0.5) 12.27
2011.10 137.3 88.0 59.9 (+0.4) 8.28
2011.11 153.5 96.7 61.1 (+1.2) 5.55
2011.12 141.3 73.0 63.4 (+2.3) 3.78
2012.01 132.5 58.3 65.5 (+2.1) 7.15
2012.02 106.5 32.9 66.9 (+1.4)
possible cycle 24 max
2012.03 114.7 64.3 66.8 (-0.1) 16.08
2012.04 113.0 55.2 64.6 (-2.2) 10.10
2012.05 121.5 69.0 (61.2 projected, -3.4) 7.06
2012.06 119.6 64.5 (58.8 projected, -2.4) 10.08
2012.07 133.9 66.5 (58.6 projected, -0.2) 13.90
2012.08 115.4 63.1 (60.4 projected, +1.8) 7.96
2012.09 122.9 61.5 (61.8 projected, +1.4) 8.07
2012.10 123.3 53.3 (61.5 projected, -0.3) 9.97
2012.11 122.3 (1) 82.2 (2A) / 91.3 (2B) / 57.9 (2C) (61.2 projected, -0.3) (7.74)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
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) Boulder SN current month average to date. 2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international Potsdam WDC 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.