Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 28, 2013 at 06:15 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update November 2, 2013)] [Cycle 24 progress (last update November 2, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update November 2, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update November 2, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update November 3, 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 very quiet on November 27. Solar wind speed at SOHO ranged between 270 and 343 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 129.0 (decreasing 13.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 126.3. The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.6). Three hour interval K indices: 11001100 (planetary), 11101210 (Boulder).

The background x-ray flux was at the class B6 level.

At the time of counting spots (see image time) spots were observed in 11 active regions in 2K resolution (SN: 209) and 8 active regions in 1K resolution (SN: 122) SDO images on the visible solar disk.

Region 11903 [S11W57] was quiet and stable.
Region 11905 [N18E19] decayed slowly and quietly.
Region 11906 [S16E13] was quiet and stable.
Region 11907 [S09E04] developed further and was quiet.
New region 11908 [S26E42] emerged on November 26 and was numbered the next day by SWPC.
New region 11909 [S18E73] rotated into view.

Spotted regions not numbered by SWPC:
New region S2860 [N00W00] emerged with several spots.
New region S2862 [S05W05] emerged with penumbra spots.
New region S2863 [N22E50] emerged with a penumbra spot in an old plage area.
New region S2864 [S08E10] emerged with a few spots aligned on a north-south axis.
New region S2865 [S66E31] emerged at a very high latitude with a penumbra spot.

Coronal mass ejections (CMEs)

November 25-26: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
November 27: Several CMEs were observed during the day. The largest had its origin in a filament eruption that began late on November 26 in the southwest quadrant (and across the limb to the backside). While Earth is not in the path of the core CME, there's a slight chance of a glancing blow on November 30.

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

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is good. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on November 28-30 with a slight chance of unsettled and active intervals on November 30 due to a CME.

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
S2837 2013.11.16       N15W60         plage
11903 2013.11.17 2 2 2 S12W58 0100 CSO HSX area: 0140
S2845 2013.11.18       S33W36           plage
S2851 2013.11.21       S10W56           plage
11907 2013.11.22
2013.11.26
11 30 13 S10E04 0060 DAO DAI area: 0290
11905 2013.11.22
2013.11.23
5 5   N18E21 0010 BXO BXO  
S2855 2013.11.22       S31W47           plage
11906 2013.11.23
2013.11.25
  7 1 S17E14 0010   BXO  
11908 2013.11.26
2013.11.27
6 19 7 S25E43 0060 DAO DAI area: 0200
11909 2013.11.26
2013.11.27
2 19 9 S18E69 0140 DSO DAC location: S18E73

area: 0350

S2860 2013.11.27   7 4 N00W00 0025   CRO    
S2862 2013.11.27   2 2 S05W05 0008   BXO    
S2863 2013.11.27   1   N22E50 0002   AXX    
S2864 2013.11.27   6 4 S08E10 0030   DRO    
S2865 2013.11.27   1   S66E31 0005   AXX    
Total spot count: 26 99 42  
Sunspot number: 76 209 122  (total spot count + 10 * number of spotted regions)
Weighted SN: 46 125 68  (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 73 67 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
2012.07 133.9 66.5 57.8 (-1.1) 13.90
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 (59.3 projected, +1.4) 9.73
2013.06 110.1 52.5 (59.7 projected, +0.4) 12.60
2013.07 115.5 57.0 (60.0 projected, +0.3) 9.47
2013.08 114.6 66.0 (60.3 projected, +0.3) 8.27
2013.09 102.6 36.9 (60.2 projected, -0.1) 5.23
2013.10  132.1 85.6 (58.7 projected, -1.5) 7.71
2013.11  150.3 (1) 115.8 (2A) / 128.6 (2B) / 82.5 (2C) (56.6 projected, -2.1) (5.8)

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.