Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 2, 2013 at 05:35 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 November 2, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet to unsettled on December 1. Solar wind speed at SOHO ranged between 443 and 633 km/s under the influence of weak CME effects.

Solar flux measured at 20h UTC on 2.8 GHz was 130.5 (decreasing 16.8 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 127.2. The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 7.3). Three hour interval K indices: 33212101 (planetary), 33323211 (Boulder).

The background x-ray flux was at the class B5 level.

At the time of counting spots (see image time) spots were observed in 16 active regions in 2K resolution (SN: 319) and 9 active regions in 1K resolution (SN: 158) SDO images on the visible solar disk.

Region 11905 [N18W32] reemerged with penumbra spots.
Region 11906 [S14W42] developed as new flux emerged.
Region 11907 [S09W48] decayed significantly and was quiet.
Region 11908 [S26W09] decayed slowly and quietly.
Region 11909 [S17E19] developed slowly and quietly. The region has many spots but only minor polarity intermixing.
Region 11910 [N02W53] decayed slowly and quietly.
Region 11911 [S11E03] was quiet and stable.

Spotted regions not numbered by SWPC:
S2868 [S18W05] developed slowly and quietly.
S2870 [S11E30] decayed slowly and quietly.
S2871 [N21E55] decayed slowly and quietly.
S2872 [N23W00] was quiet and stable.
S2873 [N15W06] was quiet and stable.
New region S2876 [S13E55] emerged with penumbra spots in an old plage area.
New region S2877 [S21E82] rotated into view.
New region S2878 [S27E44] emerged with penumbra spots.
New region S2879 [S29E18] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

November 29-30: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery, many CMEs with a backsided origin was observed.
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 likely rotate to a potentially geoeffective 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 to fair.

Forecast

The geomagnetic field is expected to be quiet on December 2-3. 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
3 4   S09W49 0030 HRX BXO  
11905 2013.11.22
2013.11.23
  8   N18W35 0011   BXO   location: N18W32
11906 2013.11.23
2013.11.25
  13 6 S17W42 0050   DRI location: S14W42
11908 2013.11.26
2013.11.27
12 23 10 S26W10 0180 EAO ESO area: 0220
11909 2013.11.26
2013.11.27
23 57 33 S18E20 0350 DKC ESC

area: 0530

location: S17E19

11910 2013.11.27
2013.11.28
8 13 6 N02W54 0040 DAO DRI  
S2863 2013.11.27       N22W02           plage
S2864 2013.11.27       S08W42           plage
S2866 2013.11.28       S30E17           plage
11911 2013.11.29
2013.11.28
8 20 7 S12E01 0050 DAO DAI area: 0090

location: S11E03

S2868 2013.11.29   7 3 S18W05 0030   CRO  
S2870 2013.11.30   1 1 S11E30 0005   AXX  
S2871 2013.11.30   2   N21E55 0003   AXX  
S2872 2013.11.30   1   N23W00 0002   AXX  
S2873 2013.11.30   2   N15W06 0007   AXX  
S2874 2013.11.30       S07E03         plage
S2875 2013.11.30       N08W43         plage
S2876 2013.12.01   3   S13E55 0005   AXX    
S2877 2013.12.01   1 1 S21E82 0170   HSX    
S2878 2013.12.01   3 1 S27E44 0010   BXO    
S2879 2013.12.01   1   S29E18 0002   AXX    
Total spot count: 54 159 68  
Sunspot number: 104 319 158  (total spot count + 10 * number of spotted regions)
Weighted SN: 72 188 97  (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): 62 112 87 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
2013.12 130.5 (1) 3.4 (2A) / 104.0 (2B) / 81.0 (2C) (56.1 projected, -1.2) (7.3)

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.