Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 23, 2015 at 04:20 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 quiet to active on December 22. Solar wind speed at SOHO ranged between 324 and 447 km/s.

Solar flux at 20h UTC on 2.8 GHz was 130.1 (increasing 21.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 107.2. The Potsdam WDC planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 11.6). Three hour interval K indices: 32342122 (planetary), 22342122 (Boulder).

The background x-ray flux is at the class B7 level.

At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 132) and 5 active regions using 1K resolution (SN: 82) SDO images on the visible solar disk.

Region 12470 [N13W51] was quiet. The large penumbra gained area.
Region 12472 [N04E65] has a small magnetic delta in the southern part of a central penumbra. M class flaring is possible.
Region 12473 [S21E62] developed quickly as a compact region. A major flare is possible. The region was the source of an M4.7 flare at 00:40 UT on December 23.
New region 12474 [N08W50] emerged on December 21 and was numbered by SWPC the next day as the region began to decay.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4976 [S17W06] was quiet and stable.
S4978 [N13E28] was quiet and stable.
New region S4981 [S07E62] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
C3.8 00:51   12472 SDO/EVE  
M1.6 03:34 S23E75 12473 GOES15  
C3.1 05:17   12473 SDO/EVE reported by Learmonth as well
C6.3 13:38 N07E74 12472 GOES15  
C4.1/1F 14:41   12473 GOES15  

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

Coronal mass ejections (CMEs)

December 20-22: 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]

No obvious coronal holes are currently in or near Earth facing positions.

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 on December 23-25.

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). 4K resolution. Compare to the previous day's image.
As of December 12, 2015, the active region maps are based on image products from semi-automated sunspot counting at 4K resolution.

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
12469 2015.12.11
2015.12.12
      N19W70          

 

12470 2015.12.12 1 7 2 N13W50 0400 HHX CHO

area: 0710

12471 2015.12.14       S21W68            
S4968 2015.12.15       N20W08            
S4969 2015.12.16       S16W05            
S4970 2015.12.16       S31W37          
S4971 2015.12.18       N14W00            
S4972 2015.12.18       N29W56            
12472 2015.12.21 10 24 15 N03E62 0150 DAO DAC beta-gamma-delta

area: 0260

12473 2015.12.21 12 18 9 S23E62 0230 DAC EKC beta-gamma-delta

area: 0620

location: S21E62

S4976 2015.12.21   7 4 S17W06 0015   BXO  
S4977 2015.12.21       N18W50          
S4978 2015.12.21   2   N12E42 0003   BXO  
12474 2015.12.21
2015.12.22
5 3 2 N07W52 0010 BXO CRO  
S4981 2015.12.22   1   S07E62 0003   AXX    
Total spot count: 28 62 32  
Sunspot number: 68 132 82  (total spot count + 10 * number of spotted regions)
Weighted SN: 48 90 60  (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): 75 73 70 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 (111.9)   38.5 (2A) / 54.2 (2B) / 66.4 (2C) (62.7 projected, -1.8) (15.4)

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).
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.