Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 10, 2014 at 06:10 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 active on December 9. Solar wind speed at SOHO ranged between 509 and 718 km/s.

Solar flux at 20h UTC on 2.8 GHz was 139.7 (decreasing 13.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 150.0. The Potsdam WDC planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 12.4). Three hour interval K indices: 42223243 (planetary), 43333233 (Boulder).

The background x-ray flux is at the class B8 level.

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 174) and 9 active regions using 1K resolution (SN: 143) SDO images on the visible solar disk.

Region 12227 [S05W19] was mostly quiet and stable.
Region 12230 [S16E22] developed further and has polarity intermixing. C and minor M class flares are possible.
Region 12232 [N09E53] decayed slowly as the trailing penumbra split into several penumbrae.
New region 12233 [N02E16] emerged on December 7 with SWPC numbering the region 2 days later.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4047 [N17W37] was quiet and stable.
S4054 [S10W01] was quiet and stable.
New region S4066 [S08E78] rotated into view.
New region S4067 [N03E32] emerged with a few spots.
New region S4068 [N20E11] emerged with penumbra spots.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C2.0 03:28 S14E35 12230  
C8.6/1F 10:24 S15E31 12230  
C5.4/1F 12:34 S16E30 12230  
C4.5 13:48 SW limb    
C6.2 15:28   12230  
C2.5 17:18   12230  
C5.3 18:48   12230  

Coronal mass ejections (CMEs)

December 7-9: 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 10-12.

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 unsettled on December 10-12.

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
12225 2014.11.29
2014.11.30
      S15W62         plage
12227 2014.12.02 3 13 8 S04W21 0150 CSO DAO

 

S4047 2014.12.02   3 1 N17W37 0006   BXO  
S4048 2014.12.02       N07W26           plage
12228 2014.12.03
2014.12.04
      N08W86           plage
S4054 2014.12.03   4 2 S10W01 0010   BXO  
12229 2014.12.04
2014.12.06
      S23W19         plage
S4057 2014.12.04       S14W29           plage
12230 2014.12.05
2014.12.06
8 34 22 S14E22 0100 DAO DAC beta-gamma

area: 0230

S4061 2014.12.06       S20W46         plage
12231 2014.12.07 5     S03W13 0010 BXO       merged with AR 12227
12232 2014.12.07 11 18 11 N10E49 0240 DAI DAC location: N09E53
12233 2014.12.07
2014.12.09
3 4 3 N02E14 0010 AXX CRO  
S4066 2014.12.09   1 1 S08E78 0200   HSX    
S4067 2014.12.09   4 4 N03E32 0020   DRO    
S4068 2014.12.09   3 1 N20E11 0005   BXO    
Total spot count: 30 84 53  
Sunspot number: 80 174 143  (total spot count + 10 * number of spotted regions)
Weighted SN: 45 110 79  (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): 48 61 79 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
2014.12 145.7 (1)   30.8 (2A) / 106.2 (2B) / 89.2 (2C) (66.0 projected, -1.7) (10.9)

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.