Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 24, 2015 at 08:10 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 quiet to unsettled on December 23 under the influence of a moderately high speed coronal hole stream (undetermined source). Solar wind speed at SOHO ranged between 405 and 470 km/s.

Solar flux at 20h UTC on 2.8 GHz was 133.9 (increasing 30.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 107.5. The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.0). Three hour interval K indices: 22122233 (planetary), 22322222 (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 4 active regions using 2K resolution (SN: 102) and 3 active regions using 1K resolution (SN: 59) SDO images on the visible solar disk.

Region 12470 [N13W64] was quiet and stable.
Region 12472 [N04E52] decayed and lost the magnetic delta. The region still has polarity intermixing and could produce a minor M class flare.
Region 12473 [S21E49] developed further and has at least one magnetic delta in the central section. A major flare is possible.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4968 [N18W13] reemerged with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
M4.7/1F 00:40 S22E63 12473 GOES15 small, narrow CME, southeastwards directed
C7.5 04:14 N05E65 12472 GOES15  

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

Coronal mass ejections (CMEs)

December 21-23: 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 fair.

Forecast

The geomagnetic field is expected to be quiet to active on December 24 due to a coronal hole high speed stream and quiet to unsettled on December 25-26.

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
      N19W84          

 

12470 2015.12.12 1 4 1 N12W66 0320 HHX CHO

area: 0630

location: N13W64

12471 2015.12.14       S21W82            
S4968 2015.12.15   5   N18W13 0010   BXO images/AR_S4968_20151223_2345.png    
S4969 2015.12.16       S16W18            
S4970 2015.12.16       S31W50            
12472 2015.12.21 10 20 12 N04E49 0170 DAI DAC beta-gamma

location: N04E52

12473 2015.12.21 11 33 16 S23E49 0420 EKC EKC beta-gamma-delta

area: 0860

location: S21E49

S4976 2015.12.21       S17W19          
S4978 2015.12.21       N12E29          
12474 2015.12.21
2015.12.22
1     N08W63 0000 AXX      
S4981 2015.12.22       S07E49          
Total spot count: 23 62 29  
Sunspot number: 63 102 59  (total spot count + 10 * number of spotted regions)
Weighted SN: 48 87 54  (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): 69 56 50 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 (112.9)   40.5 (2A) / 54.6 (2B) / 65.6 (2C) (62.7 projected, -1.8) (15.1)

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.