Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 22, 2015 at 04:35 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 major storm on December 21 under the influence of CME effects. Solar wind speed at SOHO ranged between 361 and 491 km/s.

Solar flux at 20h UTC on 2.8 GHz was 121.7 (increasing 8.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 107.1. The Potsdam WDC planetary A index was 36 (STAR Ap - based on the mean of three hour interval ap indices: 36.4). Three hour interval K indices: 66543213 (planetary), 66553222 (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 9 active regions using 2K resolution (SN: 147) and 5 active regions using 1K resolution (SN: 72) SDO images on the visible solar disk.

Region 12470 [N13W38] decayed slowly and was mostly quiet.
New region 12472 [N03E78] rotated into view as a compact region with several clustered spots. Further M class flaring is likely.
New region 12473 [S21E75] is a compact and developing region. Further M class flaring is possible (an M1.6 event was recorded at 03:34 UT on December 22).

Spotted regions not numbered (or interpreted differently) by SWPC:
S4970 [S31W24] was quiet and stable.
New region S4976 [S16E08] emerged early in the day with several spots and has polarity intermixing. C flares will be possible if the region continues to develop.
New region S4977 [N18W37] emerged early in the day as a bipolar region, then decayed and has only a single tiny spot left at the end of the day.
New region S4978 [N12E42] was observed with tiny spots.
New region S4979 [N07W38] emerged with several spots.
New region S4980 [S13W55] emerged with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
M2.8 01:03 N03E90 12472 GOES15  
C2.7 02:48 N05E87 12472 SDO/EVE  
C2.4 03:16   12472 GOES15 C3.0 @ SDO/EVE
C2.0 04:58   12472 GOES15  
C9.1 05:39   12472 GOES15  
M1.1/1N 10:19 N04E85 12472 GOES15  
C7.6 11:01   12472 SDO/EVE  
C2.2 12:49   12472 SDO/EVE reported by San Vito as well
C2.1/1F 14:33 S22E79 12473 GOES15  
C6.2 18:27   12473 GOES15  
C3.3 00:14 (on December 22) S22E77 12473 GOES15  

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

Coronal mass ejections (CMEs)

December 19-21: 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 to unsettled on December 22. Quiet conditions are likely on December 23-24.

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
12468 2015.12.09
2015.12.10
      S14W81          
12469 2015.12.11
2015.12.12
      N19W56          

 

12470 2015.12.12 3 14 5 N14W35 0410 CHO CHO

area: 0560

location: N13W38

12471 2015.12.14       S21W54            
S4968 2015.12.15       N20E05          
S4969 2015.12.16       S16E08            
S4970 2015.12.16   2   S31W24 0004   AXX  
S4971 2015.12.18       N14E13            
S4972 2015.12.18       N29W43            
12472 2015.12.21 1 12 4 N04E78 0060 HAX DAC   beta-gamma

area: 0230

12473 2015.12.21 4 10 6 S22E79 0030 CSO DAC   beta-gamma-delta

area: 0280

S4976 2015.12.21   6 4 S16E08 0020   CRI   beta-gamma
S4977 2015.12.21   1   N18W37 0002   AXX    
S4978 2015.12.21   2   N12E42 0002   BXO    
S4979 2015.12.21   8 3 N07W38 0030   DRI    
S4980 2015.12.21   2   S13W55 0004   BXO    
Total spot count: 8 57 22  
Sunspot number: 38 147 72  (total spot count + 10 * number of spotted regions)
Weighted SN: 28 83 48  (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): 42 81 61 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 (111.1)   36.3 (2A) / 53.6 (2B) / 66.8 (2C) (62.7 projected, -1.8) (15.5)

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).
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.