Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 21, 2013 at 04:00 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 quiet on November 20. Solar wind speed at SOHO ranged between 348 and 454 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 147.0 (decreasing 13.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 125.4. The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.4). Three hour interval K indices: 21111000 (planetary), 11113211 (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 10 active regions in 2K resolution (SN: 191) and 8 active regions in 1K resolution (SN: 112) SDO images on the visible solar disk.

Region 11895 [S17W63] decayed slowly. C5+ flare: C6.4 at 17:22 UTC
Region 11896 [N10W58] was quiet and stable.
Region 11899 [N06W30] gained small spots. There's a small chance of a major flare.
Region 11903 [S11E37] developed slowly and quietly.

Spotted regions not numbered by SWPC:
S2834 [N11W41] reemerged with penumbra spots.
S2837
[N14E34] was quiet and stable.
S2838 [S11W40] reemerged with penumbra spots.
S2839 [S14W03] was quiet and stable.
S2843
[N08E18] was quiet and stable.
New region S2848 [S10W34] emerged slowly and quietly.

Coronal mass ejections (CMEs)

November 18, 20: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
November 19: A halo CME was observed after the X1 event in AR 11893. Most of the ejecta was observed off the southwest limb and the south pole. Faint extensions were observed elsewhere.

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 an Earth facing position.

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 November 21. On November 22-23 there's a chance of weak effects from the CME observed on November 19.

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
11893 2013.11.07
2013.11.08
3     S13W91 0260 DKC    

rotated out of view

11895 2013.11.09
2013.11.10
2 11 3 S17W70 0020 HSX CRO

area: 0070

location: S17W63

includes AR 11897

11896 2013.11.10 1 3 3 N10W58 0090 HAX CSO

 

11897 2013.11.11 5     S18W58 0040 DSO       magnetically part of 11895
11899 2013.11.12 7 38 13 N07W29 0560 DKO DKO

area: 0850

S2828 2013.11.12       S16W39           plage
11900 2013.11.12
2013.11.14
4     S23W88 0060 CSO     rotated out of view
11902 2013.11.13
2013.11.14
      N20W75         plage
S2834 2013.11.14   2   N11W41 0005   AXX    
S2835 2013.11.14       N01W21           plage
S2837 2013.11.16   5 2 N14E34 0011   BXO  
S2838 2013.11.16   2   S11W40 0008   BXO    
S2839 2013.11.16   14 3 S14W03 0030   BXO images\AR_S2839_20131120_2345.png  
11903 2013.11.17 3 10 5 S12E36 0150 HAX DSO area: 0240
S2843 2013.11.17   3 2 N09E05 0009   AXX  
S2844 2013.11.18       S04E21           plage
S2845 2013.11.18       S33E55           plage
S2846 2013.11.18       S23E19           plage
S2848 2013.11.20   3 1 S11W40 0012   CRO   plage
Total spot count: 25 91 32  
Sunspot number: 95 191 112  (total spot count + 10 * number of spotted regions)
Weighted SN: 70 117 58  (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): 57 67 59 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  157.4 (1) 101.0 (2A) / 151.5 (2B) / 91.7 (2C) (56.6 projected, -2.1) (6.4)

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.