Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 4, 2013 at 06:10 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update December 1, 2013)] [Cycle 24 progress (last update December 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update December 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update December 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update December 1, 2013)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated December 3, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet to unsettled on December 3. Solar wind speed at SOHO ranged between 356 and 436 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 135.7 (decreasing 17.8 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 127.7. The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 7.4). Three hour interval K indices: 12123222 (planetary), 11143222 (Boulder).

The background x-ray flux was at the class B7 level.

At the time of counting spots (see image time) spots were observed in 17 active regions in 2K resolution (SN: 292) and 12 active regions in 1K resolution (SN: 175) SDO images on the visible solar disk.

Region 11905 [N17W58] was quiet and stable.
Region 11906 [S14W70] developed slowly and was quiet. C flares are possible.
Region 11908 [S26W36] decayed slowly and quietly.
Region 11909 [S17W08] decayed slowly and quietly.
Region 11911 [S10W23] decayed slowly and quietly.
Region 11912 [S21E55] was quiet and stable.
Region 11914 [S17W24] decayed slowly and quietly.
New region 11915 [S28W08] emerged on December 1 and was numbered by SWPC 2 days later.

Spotted regions not numbered by SWPC:
S2872 [N23W26] reemerged with a penumbra spot.
S2876 [S14E23] gained leading penumbra spots.
S2880 [S13W10] was quiet and stable.
S2881 [N10W01] decayed slowly and quietly.
S2882 [N24E07] decayed slowly and quietly.
S2884 [N10W76] matured and was quiet.
New region S2886 [S25E16] emerged with penumbra spots.
New region S2887 [N08E25] emerged with a penumbra spot.
New region S2888 [N04W37] emerged with a penumbra spot.

An active region at the southeast limb has produced flares early on December 4.

Coronal mass ejections (CMEs)

December 2-3: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
December 1: A filament eruption in the northwest quadrant began near 19:30 UTC and a partial halo CME was observed in LASCO and STEREO imagery after 21:30 UTC.

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 trans equatorial coronal hole (CH596) will rotate to an Earth facing position on December 3-4.

Coronal hole map

Propagation

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.

Forecast

The geomagnetic field is expected to be quiet to unsettled on December 4-5. There's a chance of unsettled intervals on December 4 due to weak effects from CH595. A glancing blow from the CME observed on December 1 is possible on December 4 and could cause unsettled and active intervals. On December 6-7 unsettled to active conditons are likely due to effects from CH596.

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 2K resolution) 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 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
11907 2013.11.22
2013.11.26
      S09W77           plage
11905 2013.11.22
2013.11.23
  1   N18W63 0002   AXX location: N17W58
11906 2013.11.23
2013.11.25
  17 7 S17W70 0160   DAI location: S14W70

SWPC: AR 11914

11908 2013.11.26
2013.11.27
5 12 9 S26W34 0080 DSO ESO area: 0140
11909 2013.11.26
2013.11.27
17 42 20 S18W07 0250 EKC ESC

area: 0420

11910 2013.11.27
2013.11.28
      N02W81         plage
S2866 2013.11.28       S30W09           plage
11911 2013.11.29
2013.11.28
2 6 4 S11W24 0020 HRX CAO

area: 0040

11914 2013.11.29
2013.12.02
  4 2 S17W24 0008 AXX BXO  
S2870 2013.11.30       S11E04           plage
S2871 2013.11.30       N21E27         plage
S2872 2013.11.30   1 1 N23W26 0004   AXX    
S2873 2013.11.30       N15W32           plage
S2874 2013.11.30       S07W23           plage
S2876 2013.12.01   16 1 S14E23 0032   BXO images/AR_S2876_20131203_2345.png images\AR_S2876_20131202_2345.png  
11912 2013.12.01
2013.12.02
1 8 1 S21E53 0120 HSX HSX area: 0200

location: S21E55

S2878 2013.12.01       S27E18           plage
11915 2013.12.01
2013.12.03
3 11 5 S29W08 0010 BXO DAI area: 0090
11913 2013.12.02 9     S15W69 0090 CAO       actually AR 11906
S2880 2013.12.02   6 2 S13W10 0024   BXO  
S2881 2013.12.02   2   N10W01 0002   BXO  
S2882 2013.12.02   1   N24E07 0001   AXX  
S2883 2013.12.02       S06W11         plage
S2884 2013.12.02   1 1 N10W76 0020   HRX  
S2886 2013.12.03   2 2 S25E16 0016   BXO    
S2887 2013.12.03   1   N08E25 0001   AXX    
S2888 2013.12.03   1   N04W37 0001   AXX    
Total spot count: 37 132 55  
Sunspot number: 97 292 175  (total spot count + 10 * number of spotted regions)
Weighted SN: 65 165 88  (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): 58 102 96 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)
2011.11 153.5 (cycle peak) 96.7 (cycle peak) 61.1 (+1.2) 5.55
2012.02 106.5 32.9 66.9 (+1.4)
possibe cycle 24 max
8.81
2012.08 115.4 63.0 58.2 (+0.4) 7.96
2012.09 122.9 61.4 58.1 (-0.1) 8.07
2012.10 123.3 53.3 58.6 (+0.5) 9.97
2012.11 121.3 61.8 59.7 (+1.1) 7.08
2012.12 108.6 40.8 59.6 (-0.1) 3.44
2013.01 127.1 62.9 58.7 (-0.9) 4.69
2013.02 104.3 38.0 58.4 (-0.3) 6.11
2013.03 111.3 57.9 57.5 (-0.9) 10.56
2013.04 124.8 72.4 57.9 (+0.4) 5.40
2013.05 131.4 78.7 59.9 (+2.0) 9.73
2013.06 110.1 52.5 (61.5 projected, +1.6) 12.60
2013.07 115.5 57.0 (62.1 projected, +0.6) 9.47
2013.08 114.6 66.0 (62.3 projected, +0.2) 8.27
2013.09 102.6 36.9 (61.2 projected, -1.1) 5.23
2013.10  132.1 85.6 (59.0 projected, -2.2) 7.71
2013.11  148.3 77.6 (57.3 projected, -1.7) 5.7
2013.12 133.3 (1) 10.5 (2A) / 108.3 (2B) / 82.0 (2C) (56.1 projected, -1.2) (5.6)

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 the 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.