Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 3, 2013 at 05:05 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 very quiet on December 2. Solar wind speed at SOHO ranged between 348 and 530 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 133.7 (decreasing 14.8 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 127.4. 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: 10000000 (planetary), 00001211 (Boulder).

The background x-ray flux was at the class B4 level.

At the time of counting spots (see image time) spots were observed in 16 active regions in 2K resolution (SN: 290) and 12 active regions in 1K resolution (SN: 178) SDO images on the visible solar disk.

Region 11905 [N18W48] was quiet and stable.
Region 11906 [S14W57] developed slowly and quietly (SWPC failed to reuse 11906 and is using AR 11913 instead).
Region 11908 [S26W21] decayed slowly and quietly.
Region 11909 [S17E06] decayed slowly losing penumbral area and spots.
Region 11910 [N01W66] decayed slowly and quietly losing the leading spots.
Region 11911 [S11W10] decayed slowly and quietly.
New region 11912 [S21E68] rotated into view on December 1 and was numbered by SWPC the next day.
New region 11914 [S17W17] emerged on November 28 and was detected by SWPC 4 days later. The region decayed significantly on Dec.2.

Spotted regions not numbered by SWPC:
S2871 [N21E40] was quiet and stable.
S2876 [S14E30] gained leading penumbra spots.
S2879 [S29E05] was quiet and stable.
New region S2880 [S13E04] emerged near AR 11909 with several penumbra spots.
New region S2881 [N10E12] emerged with a few penumbra spots.
New region S2882 [N23E17] emerged with a penumbra spot.
New region S2883 [S06E02] emerged with a penumbra spot.
New region S2884 [N10W62] emerged with penumbra spots.

Coronal mass ejections (CMEs)

November 30, December 2: 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 coronal hole (CH595) was in an Earth facing position on November 30 - December 1, however, the coronal hole is small and may be too far to the north to cause geomagnetic effects. 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 poor.

Forecast

The geomagnetic field is expected to be quiet on December 3. 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
      S09W63         plage
11905 2013.11.22
2013.11.23
  2 1 N18W49 0008   BXO location: N18W32
11906 2013.11.23
2013.11.25
  15 8 S17W56 0100   DAI location: S14W57

SWPC: now AR 11914

11908 2013.11.26
2013.11.27
9 17 6 S25W22 0120 EAO ESI area: 0180
11909 2013.11.26
2013.11.27
27 47 23 S17E06 0330 EKC ESC

area: 0480

11910 2013.11.27
2013.11.28
5 3 2 N02W67 0010 BXO AXX location: N01W66
S2863 2013.11.27       N22W15           plage
S2864 2013.11.27       S08W55           plage
S2866 2013.11.28       S30E04           plage
11911 2013.11.29
2013.11.28
6 9 6 S11W10 0050 DAO CAO

 

11914 2013.11.29
2013.12.02
2 7 4 S18W19 0010 AXX BXO  
S2870 2013.11.30       S11E17         plage
S2871 2013.11.30   3   N21E40 0005   BXO  
S2872 2013.11.30       N23W13         plage
S2873 2013.11.30       N15W19         plage
S2874 2013.11.30       S07W10           plage
S2875 2013.11.30       N08W56           plage
S2876 2013.12.01   9   S14E30 0020   BXO images\AR_S2876_20131202_2345.png  
11912 2013.12.01
2013.12.02
1 2 1 S21E66 0080 HSX HSX area: 0170

location: S21E68

S2878 2013.12.01       S27E31         plage
S2879 2013.12.01   1 1 S29E05 0007   AXX  
11913 2013.12.02 4     S13W56 0040 DAO       actually AR 11906
S2880 2013.12.02   7 3 S13E04 0017   BXO    
S2881 2013.12.02   4 2 N10E12 0022   BXO    
S2882 2013.12.02   1 1 N23E17 0005   AXX    
S2883 2013.12.02   1   S06E02 0003   AXX    
S2884 2013.12.02   2   N10W62 0007   BXO    
Total spot count: 54 130 58  
Sunspot number: 124 290 178  (total spot count + 10 * number of spotted regions)
Weighted SN: 84 155 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): 74 102 98 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
2013.12 132.1 (1) 7.4 (2A) / 114.0 (2B) / 81.5 (2C) (56.1 projected, -1.2) (4.7)

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.