Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 12, 2015 at 06:10 UT.

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data from 2003.01 (December 3, 2015)
Solar cycle Solar cycles 23-24 (December 1, 2015) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (December 1, 2015) Noon SDO sunspot count 1K Reference: 4K (large file) (*)
  Solar cycles 1-24 (July 17, 2015) POES auroral activity level October 2009 - December 2012
  Comparison of cycles 21, 22, 23 and 24 (December 1, 2015) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12, 13, 14, 16 and 24 (December 1, 2015) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (November 16, 2015)  

Recent activity

The geomagnetic field was unsettled to active on December 11 under the influence of a high speed stream from CH704. Solar wind speed at SOHO ranged between 571 and 664 km/s.

Solar flux at 20h UTC on 2.8 GHz was 113.7 (increasing 7.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 105.7. The Potsdam WDC planetary A index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 17.4). Three hour interval K indices: 43333433 (planetary), 44332333 (Boulder).

The background x-ray flux is at the class B5 level.

At the time of counting spots (see image time), spots were observed in 12 active regions using 2K resolution (SN: 181) and 8 active regions using 1K resolution (SN: 102) SDO images on the visible solar disk.

Region 12462 [N08W31] decayed slowly and quietly.
Region 12463 [S09W33] decayed slowly and quietly.
Region 12464 [S11W10] decayed slowly and quietly.
Region 12465 [S06E09] produced the two most energetic flares of the day with the first flare triggering the second one.
Region 12466 [S14W21] decayed slowly and was quiet.
Region 12467 [S05W13] decayed slowly and quietly.
Region 12468 [S15E54] developed a magnetic delta in the trailing penumbra. C flares are likely and there is a chance of a minor M class event.

Spotted regions not numbered (or interpreted differently) by SWPC:
New region S4956 [N13E46] was observed with tiny spots.
New region S4957 [N17E82] rotated partly into view. The region has been fairly active early on December 12 producing C flares, the largest a C5 event at 05:28 UT. M class flares may be possible.
New region S4958 [S25W20] was observed with a tiny spot.
New region S4959 [N10W12] was observed with a tiny spot.
New region S4960 [S18E09] was observed with a tiny spot.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C3.2 16:53 S05E18 12465 SDO/EVE  
C5.6/1F 17:16 S06E16 12465 GOES15  

Flare activity (SDO/EVE/ESP XRS-B proxy)

Coronal mass ejections (CMEs)

December 9-11: No obviously Earth directed CMEs were observed in available 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 large recurrent northern hemisphere coronal hole (CH704) with a very long trans equatorial extension was in an Earth facing position on December 2-8. A recurrent northern hemisphere coronal hole (CH705) will rotate across the central meridian on December 11-13.

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 fair.

Forecast

The geomagnetic field is expected to be quiet to active on December 12 due to effects from CH704. Quiet to unsettled is likely on December 13 becoming quiet to active on December 14-15 due to effects from CH705.

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 overlays
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12462 2015.12.02
2015.12.03
  2   N10W38 0002   AXX

location: N08W31

12463 2015.12.03 3 6 2 S08W35 0020 CRO CRO

 

12466 2015.12.04
2015.12.08
4 6 3 S13W22 0010 BXO CRO  

area: 0025

12464 2015.12.04
2015.12.05
3 13 4 S10W10 0010 CRO BXO  
S4942 2015.12.05       N15W41            
12465 2015.12.06
2015.12.07
2 10 4 S05E09 0050 HAX CAO

area: 0090

 

S4945 2015.12.06       N10W10            
12467 2015.12.08
2015.12.09
1 5 1 S05W13 0000 AXX BXO  
12468 2015.12.09
2015.12.10
4 10 5 S14E52 0070 DAO DAC beta-delta

location: S15E54

S4952 2015.12.09       S22E35          
S4953 2015.12.10       S01E05          
S4954 2015.12.10       N16W47          
S4955 2015.12.10       S22W45          
S4956 2015.12.11   4 2 N13E46 0010   BXO    
S4957 2015.12.11   2 1 N17E82 0040   HRX    
S4958 2015.12.11   1   S25W20 0003   AXX    
S4959 2015.12.11   1   N10W12 0003   AXX    
S4960 2015.12.11   1   S18E09 0003   AXX    
Total spot count: 17 61 22  
Sunspot number: 77 181 102  (total spot count + 10 * number of spotted regions)
Weighted SN: 33 80 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): 85 100 87 k * (sunspot number)
As of July 1, 2015: k = 1.1 for SWPC, k = 0.55 for MSN 2K, k = 0.85 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO) (4)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2014.02 170.3
(cycle peak)
166.3 146.1 (cycle peak) 110.5 (+1.2) 10.70
2014.04 143.9 144.8 112.5 116.4 (+2.1) (solar max) 7.88
2014.10 153.4 152.9 90.0 97.3 (-4.6) 8.96
2014.11 154.8 151.4 103.6 94.7 (-2.6) 9.33
2014.12 158.7 153.8 112.9 92.2 (-2.5) 11.24
2015.01 141.9 137.3 93.0 89.3 (-2.9) 9.46
2015.02 129.1 126.0 66.7 86.1 (-3.2) 9.92
2015.03 125.9 124.6 54.5 82.2 (-3.9) 16.14
2015.04 128.8 129.7 75.3 78.9 (-3.3) 10.73
2015.05 120.0 122.6 88.8 76.0 (-2.9) 8.29
2015.06 122.3 126.1 66.5 (72.1 projected, -3.9) 13.15
2015.07 107.0 110.8 66.4 (68.4 projected, -3.7) 8.83
2015.08 105.4 108.0 64.6 (67.2 projected, -1.2) 14.58
2015.09 101.7 102.7 78.1 (67.4 projected, +0.2) 15.78
2015.10 104.1 103.3 61.7 (66.5 projected, -0.9) 14.02
2015.11 109.3 106.9 63.2 (64.5 projected, -2.0) 12.09
2015.12 (102.0)   17.8 (2A) / 50.2 (2B) / 72.7 (2C) (62.7 projected, -1.8) (11.9)

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).
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.
4) Updated to new data set from WDC-SILSO on July 1, 2015

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 Universal Time. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.