Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 7, 2014 at 05:15 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, 2014)] [Cycle 24 progress (last update December 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update December 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update December 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update December 3, 2014)]

[Noon SDO sunspot count 1K Reference: 4K (large file) (updated daily)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated November 22, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to unsettled on December 6. Solar wind speed at SOHO ranged between 418 and 759 km/s. The total field of the interplanetary magnetic field increased slowly after 07h UTC and peaked near 15h UTC at a moderate to high level. This was likely the arrival of another CME embedded in the solar wind (no shock was observed).

Solar flux at 20h UTC on 2.8 GHz was 128.7 (decreasing 3.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 151.1. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 9.8). Three hour interval K indices: 22221233 (planetary), 12332234 (Boulder).

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

At the time of counting spots (see image time), spots were observed in 11 active regions using 2K resolution (SN: 166) and 8 active regions using 1K resolution (SN: 103) SDO images on the visible solar disk.

Region 12218 [N17W88] rotated quietly to the northwest limb.
Region 12221 [N02W57] was quiet and stable.
Region 12222 [S20W65] decayed slowly and produce a few C flares.
Region 12225 [S16W17] decayed slowly and quietly.
Region 12227 [S05E21] developed with new flux emerging in the trailing spot section.
New region 12229 [S24E23] emerged on December 4. The region decayed quickly on December 6 when it was numbered by SWPC.
New region 12230 [S14E60] rotated into view on December 5 with SWPC numbering the region the next day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4047 [N12E08] was quiet and stable.
S4053 [S10W37] was quiet and stable.
S4054 [S07E35] reemerged with penumbra spots.
New region S4061 [S23W02] emerged with a few spots.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C2.8 01:56 S21W48 12222  
C4.4 (LDE) 12:44 S24W53 12222  
C3.7/1N 13:52 S25W51 12222  

Coronal mass ejections (CMEs)

December 4-6: No obviously Earth directed CMEs were observed in LASCO imagery.

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 recurrent northern hemisphere coronal hole (CH645) will likely rotate into an Earth facing position on December 10.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over 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 to active on December 7 due to CME effects and quiet to unsettled on December 8-9.

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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% 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 Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12218 2014.11.23 1 1   N17W90 0090 HSX HSX

area: 0190

12221 2014.11.25
2014.11.26
  2   N05W67 0004   AXX location: N02W57
12222 2014.11.26 6 11 6 S20W64 0650 CKO CKO  
12224 2014.11.26
2014.11.28
      S24W82           plage
12226 2014.11.27
2014.12.01
1     S19W88 0010 HSX    

rotated out of view

12225 2014.11.29
2014.11.30
  3 2 S15W21 0008   BXO location: S16W17
12227 2014.12.02 1 20 7 S04E18 0100 HSX DSO

area: 0220

S4047 2014.12.02   6 1 N12E08 0010   BXO  
S4048 2014.12.02       N07E13         plage
S4049 2014.12.02       S09W40           plage
12228 2014.12.03
2014.12.04
      N08W44           plage
S4053 2014.12.03   1 1 S10W37 0004   AXX  
S4054 2014.12.03   2 1 S07E35 0004   AXX    
12229 2014.12.04
2014.12.06
3 1   S23E22 0010 BXO AXX area: 0002
S4057 2014.12.04       S14E13         plage
12230 2014.12.05
2014.12.06
1 4 2 S14E57 0010 AXX AXX location: S14E60
S4060 2014.12.05       S40W21         plage
S4061 2014.12.06   5 3 S23W02 0016   CRO    
Total spot count: 13 56 23  
Sunspot number: 73 166 103  (total spot count + 10 * number of spotted regions)
Weighted SN: 38 79 41  (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): 44 58 57 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2013.08 114.6 118.3 66.0 69.0 (+3.5) 8.27
2013.09 102.6 103.7 36.9 73.1 (+4.1) 5.23
2013.10  132.1 131.2 85.6 75.0 (+1.9) 7.71
2013.11  148.3 145.1 77.6 75.4 (+0.4) 5.68
2013.12 147.7 143.1 90.3 76.0 (+0.6) 4.68
2014.01 157.4 152.4 81.8 77.3 (+1.3) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) 78.4 (+1.1) 10.70
2014.03 149.9 148.5 91.9 80.8 (+2.4) 4.88
2014.04 143.9 144.8 84.7 81.9 (+1.1)
(likely solar max)
7.88
2014.05 129.7 132.9 75.2 80.5 (-1.4) 5.75
2014.06 122.0 125.8 71.0 (79.1 projected, -1.6) 6.72
2014.07 137.4 141.8 72.5 (77.5 projected, -1.6) 4.50
2014.08 124.7 127.9 74.7 (75.1 projected, -3.0) 7.71
2014.09 146.6 148.1 87.6 (71.9 projected, -3.2) 9.78
2014.10 153.4 152.9 60.6 (69.5 projected, -2.4) 8.96
2014.11 154.8 151.4 70.1 (67.7 projected, -1.8) 9.33
2014.12 151.2 (1)   23.9 (2A) / 123.5 (2B) / 90.7 (2C) (66.0 projected, -1.7) (8.6)

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 WDC-SILSO 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 GFZ 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.