Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 23, 2012 at 04:35 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 June 27, 2011]

Recent activity

The geomagnetic field was very quiet on November 22. Solar wind speed at SOHO ranged between 339 and 371 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 127.7 (decreasing 3.0 over the last solar rotation). The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.1). Three hour interval K indices: 10000001 (planetary), 00002211 (Boulder).

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

At midnight UTC the visible solar disk had 9 spotted active regions (in 2K resolution SDO images).

Region 11613 [S23W85] rotated quietly to the southwest limb.
Region 11616 [N19W42] decayed slowly and quietly.
Region 11618 [N08W14] decayed in the leading and central spot sections and became less complex as the largest magnetic delta structure disappeared. M class flares are still possible.
Region 11619 [N10W56] decayed slowly and quietly.
Region 11620 [S12E29] was quiet and stable.

Spotted regions not numbered by NOAA/SWPC:
S2059 [N08W08] has a leader spot which is difficult to separate from AR 11618 and tiny trailing spots. was quiet and stable.
S2067 [S19W02] was quiet and stable.
S2068 [N17W50] decayed signficantly and was quiet.
New region S2069 [N18E03] emerged with a tiny spot.

Coronal mass ejections (CMEs)

November 20: A full halo CME was observed after noon following a filament eruption near AR 11619. This CME could reach Earth on November 23.
November 21: While most of the ejecta from the CME associated with the M3 event in AR 11618 was directed eastwards, components of the CME could be Earth directed.
November 22: A filament eruption was observed starting in the southeast quadrant just after 08h UTC. LASCO C3 observed a faint and slow CME off the east limb from 10:42 UTC while the CME was visible in STEREO imagery from 10:09 UTC. There may be a very weak Earth directed component associated with this CME.

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

No obvious coronal holes are currently in or near Earth facing positions.

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.

Propagation

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.

Forecast

The geomagnetic field is expected to be quiet to active on November 23-24 due to CME effects and quiet to unsettled on November 25.

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
detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlay
Comment
SWPC STAR SDO SWPC STAR Current Previous
2K 1K
11613 2012.11.09
2012.11.11
1 1   S24W83 0060 HSX HSX

location: S23W85

11614 2012.11.10
2012.11.11
      N14W76          

plage

11616 2012.11.13
2012.11.14
4 3   N19W42 0030 DRO AXX area: 0000
S2055 2012.11.14       S27W52           plage
11618 2012.11.15
2012.11.17
30 34 18 N08W13 0350 EKC EKC beta-gamma-delta

area: 0600

11619 2012.11.15
2012.11.17
7 2 2 N11W51 0150 DAO HAX

location: N10W56

S2059 2012.11.16   4 1 N08W08 0030   CAO  
S2060 2012.11.17       S13W16           plage
S2061 2012.11.18       S33W06           plage
11620 2012.11.18
2012.11.20
1 6 4 S12E30 0060 HSX CSO area: 0090
S2064 2012.11.19       S21E33           plage
S2065 2012.11.19       N13W23           plage
S2066 2012.11.20       S10E05           plage
S2067 2012.11.21   3 2 S19W02 0010   BXO  
S2068 2012.11.21   6 2 N17W50 0060   DAO  
S2069 2012.11.22   1   N18E03 0000   AXX    
Total spot count: 43 60 29  
Sunspot number: 93 150 89  (total spot count + 10 * number of spotted regions)
Weighted SN: 71 95 83  (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): 56 53 49 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
(3)
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
8.81
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
2012.11 122.6 (1) 66.0 (2A) / 94.2 (2B) / 56.2 (2C) (61.2 projected, -0.3) (8.88)

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.