Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 11, 2014 at 05:40 UTC. Due to a medical problem the next update won't be until after approximately December 24.

[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 10. Solar wind speed at SOHO ranged between 449 and 546 km/s.

Solar flux at 20h UTC on 2.8 GHz was 149.8 (decreasing 3.7 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.9. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.5). Three hour interval K indices: 32221111 (planetary), 21232211 (Boulder).

The background x-ray flux is at the class B9 level.

At the time of counting spots (see image time), spots were observed in 12 active regions using 2K resolution (SN: 231) and 11 active regions using 1K resolution (SN: 163) SDO images on the visible solar disk.

Region 12227 [S05W32] was quiet and stable. The region has minor polarity intermixing.
Region 12230 [S15E08] decayed in the trailing spot section and was mostly quiet.
Region 12232 [N09E39] decayed further losing penumbral area.
Region 12233 [N01E02] decayed slowly and quietly.
New region 12234 [N03E17] emerged on December 9 and was numbered by SWPC the next day as the region continued to develop.
New region 12235 [S08E64] rotated into view on December 9 and received its NOAA number the following day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4047 [N18W35] lost the leading penumbra spot while a trailing penumbra spot emerged.
S4054 [S13W22] was quiet and stable.
New region S4069 [S12E80] rotated into view.
New region S4071 [N12E24] emerged with a penumbra spot.
New region S4072 [S12E39] was observed with penumbra spots.
New region S4073 [N29E86] rotated partly into view. C flares are possible.

A filament eruption began just before 15h UTC near AR S4054 and expanded to include a fairly large area, mostly in the southwest quadrant and extending to near the central meridian and the equator. LASCO imagery of the hours after this event is missing, therefore it is uncertain whether there was a potentially Earth directed CME or not.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C5.9 (LDE) 19:22 behind SW limb    

Coronal mass ejections (CMEs)

December 8-9: No obviously Earth directed CMEs were observed in LASCO imagery.
December 10: A filament eruption mainly in the southwest quadrant may have caused a potentially Earthbound CME. If that is the case the CME would reach Earth on December 13.

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 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 and slowly improving. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be mostly quiet on December 11-12. On December 13 there is a chance of a small CME impact. A high speed stream from CH645 will likely arrive that day and cause quiet to active conditions until December 16.

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
      S15W76           plage
12227 2014.12.02 4 10 8 S03W34 0120 CAO DAO

beta-gamma

location: S05W32

S4047 2014.12.02   1 1 N18W35 0003   AXX  
S4048 2014.12.02       N07W39           plage
S4054 2014.12.03   3 1 S13W22 0007   AXX  
12229 2014.12.04
2014.12.06
      S23W32           plage
S4057 2014.12.04       S14W42           plage
12230 2014.12.05
2014.12.06
20 48 17 S15E08 0130 DAI DAC beta-gamma

area: 0250

12231 2014.12.07       S03W28           merged with AR 12227
12232 2014.12.07 7 18 9 N10E37 0240 DAO DAO location: N09E39
12233 2014.12.07
2014.12.09
2 2 1 N03E02 0010 BXO AXX location: N01E02
12235 2014.12.09
2014.12.10
1 3 1 S07E63 0140 HSX CHO area: 0270
12234 2014.12.09
2014.12.10
3 18 12 N05E18 0020 CRO DRI beta-gamma

area: 0090

location: N03E17

S4068 2014.12.09       N20W02         plage
S4069 2014.12.10   3 1 S12E80 0080   CSO    
S4071 2014.12.10   1   N12E24 0002   AXX    
S4072 2014.12.10   3 1 S12E39 0007   AXX    
S4073 2014.12.10   1 1 N29E86 0200   HAX    
Total spot count: 37 111 53  
Sunspot number: 97 231 163  (total spot count + 10 * number of spotted regions)
Weighted SN: 60 149 91  (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): 58 81 90 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
2014.12 146.1 (1)   34.0 (2A) / 105.3 (2B) / 89.4 (2C) (66.0 projected, -1.7) (10.5)

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.