Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 31, 2021 at 15:15 UT

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data since 2003.01 (December 1, 2021)
Solar cycle Solar cycles 23-25 (December 1, 2021) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (December 1, 2021) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (June 1, 2020) POES auroral activity level October 2009 - December 2012]
  Comparison of cycles 21-25 (December 1, 2021) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (December 1, 2021) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (August 22, 2021) Cycle 25 spots (final update December 25, 2019)
  Solar cycles 24-25 transition using 365d smoothing Research: Solar Cycle 25 Started on November 17, 2019 with 365 Days Smoothing

Recent activity

The geomagnetic field was quiet to unsettled on December 30, weakly under the influence of effects from CH1051. The high latitude magnetometer at Andenes recorded quiet levels.

Solar flux density measured at 20h UT on 2.8 GHz was 102.4 - increasing 17.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 81.72). The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 6.9). Three hour interval K indices: 32222111 (planetary), 32132221 (Boulder), 20011121 (Andenes).

The background x-ray flux was at the class B3 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 8 active regions using 2K resolution (SN: 140) and in 5 active regions using 1K resolution (SN: 69) SDO/HMI images.

Region 12916 [S17W38] decayed slowly and quietly.
Region 12917 [S27W75] decayed slowly and quietly.
Region 12918 [N19W55] decayed fairly quickly and was quiet until 04:54 UT (C1.9 flare) and 06:56 UT on December 31 when a C9.8 flare was recorded. That flare triggered a filament eruption as well.
Region 12919 [S12W00] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC:
S7263 [N24W16] reemerged with a tiny spot.
New region S7270 [S29W38] emerged with tiny spots.
New region S7271 [S17E38] emerged with tiny spots.
New region S7272 [N12E29] emerged with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
           

Coronal mass ejections (CMEs)

December 28-30: 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 recurrent northern hemisphere coronal hole (CH1052) was in an Earth facing position on December 28-29.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is good. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on December 31. On January 1-2 quiet to active conditions are likely due to effects from CH1052.

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.
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 officially numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC, all other regions are numbered sequentially as they emerge using the STAR spot number. 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. SWPC data considered to be not sufficiently precise (location, area, classification) are red colored.

Active region SWPC date numbered
STAR detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlays
Comment
SWPC/
USAF
Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12912 2021.12.18
2021.12.19
      S13W83          

location: S14W76

12915 2021.12.18
2021.12.21
      N16W86            
12916 2021.12.21
2021.12.21
14 37 11 S16W36 0640 ESI EAI

beta-gamma

location: S17W35

area: 0400

S7253 2021.12.21       N24W53            
12918 2021.12.21
2021.12.22
9 8 3 N22W54 0060 BXI BXO

location: N19W55

area: 0020

12917 2021.12.21
2021.12.22
1 1   S27W76 0010 AXX AXX

area: 0003

12920 2021.12.22
2021.12.26
      S17W84         location: S17W87
12919 2021.12.24
2021.12.25
1 4 2 S11W01 0040 HRX CRO area: 0020
12921 2021.12.26
2021.12.28
2     N30W92 0300 DSO     rotated out of view
S7263 2021.12.26   1   N24W16 0002   AXX    
S7264 2021.12.26       S18W52            
S7265 2021.12.26       S20W54          
S7266 2021.12.27       S09W48            
S7267 2021.12.27       S34W40            
S7268 2021.12.28       S06W11            
S7269 2021.12.29       N18W00          
S7270 2021.12.30   3 2 S29W38 0008   BXO    
S7271 2021.12.30   3 1 S17E38 0006   BXO    
S7272 2021.12.30   3   N12E29 0003   BXO    
Total spot count: 27 60 19  
Sunspot number: 77 140 69  (total spot count + 10 * number of spotted regions)
Weighted SN: 40 68 27  (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 77 55  

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2014.02 170.3
(cycle peak)
166.3 146.1 (SC24 peak) 110.5 10.70
2014.04 143.9 144.8 112.5 116.4 (solar max) 7.88
2017.09 91.3 92.3 43.6 18.2 (-1.3) 18.22
(cycle peak)
2019.11 70.2 68.7 0.5 2.0 (-0.6)
(Solar minimum using 365d smoothing:
November 17, 2019)
4.19
2019.12 70.8 68.6 1.6 1.8 (-0.2)
(ISN 13 months smoothed
solar minimum)
3.22
2020.06 69.5 71.7 5.8 7.9 (+2.3) 3.75
2020.07 69.5 71.8 6.3 9.0 (+1.1) 4.28
2020.08 71.6 73.4 7.6 9.5 (+0.5) 5.68
2020.09 70.7 71.4 0.7 10.5 (+1.0) 8.59
2020.10 74.6 74.2 14.6 11.9 (+1.4) 6.13
2020.11 89.9 88.0 34.5 13.6 (+1.7) 4.77
2020.12 86.9 84.2 23.1 15.3 (+1.7) 4.72
2021.01 76.0 73.6 10.4 17.3 (+2.0) 4.39
2021.02 74.3 72.4 8.3 19.1 (+1.8) 9.50
2021.03 76.0 75.2 17.3 21.8 (+2.7) 10.17
2021.04 75.9 76.4 24.5 24.9 (+3.1) 8.40
2021.05 75.3 77.1 21.2 25.9 (+1.0) 6.50
2021.06 79.4 81.8 25.3 (26.9 projected, +1.0) 5.52
2021.07 81.0 83.6 34.4 (29.9 projected, +3.0) 5.51
2021.08 77.7 79.7 22.4 (34.6 projected, +4.7) 6.19
2021.09 87.0 88.2 51.5 (40.3 projected, +5.7) 6.33
2021.10 88.9 88.3 38.1 (44.7 projected, +4.4) 7.38
2021.11 86.2 84.4 35.1 (49.3 projected, +4.6) 9.83
2021.12 103.0 (1)   67.7 (2A) / 70.0 (2B) / 77.8 (2C) (55.1 projected, +5.8) (6.7)
2022.01       (58.7 projected, +3.6)  
2022.02       (63.5 projected, +4.8)  
2022.03       (68.9 projected, +5.4)  
2022.04       (74.0 projected, +5.1)  
2022.05       (80.4 projected, +6.4)  

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz and any corrections applied to that measurement.
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) Source: SIDC-SILSO.

Solar cycles 24-25

Smoothed SF and sunspot numbers

 

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.