Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 21, 2022 at 13:50 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 4, 2022)
Solar cycle Solar cycles 23-25 (December 1, 2022) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (December 1, 2022) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (July 1, 2020) POES auroral activity level [October 2009 - December 2012]
  Comparison of cycles 21-25 (December 1, 2022) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (December 1, 2022) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (August 21, 2022) 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 on December 20. Solar wind speed at SOHO ranged between 335 and 445 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels.

Solar flux density measured at 20h UT on 2.8 GHz was 146.4 - increasing 33.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 123.62). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.6). Three hour interval K indices: 11110122 (planetary), 11111322 (Boulder), 31100133 (Andenes).

The background x-ray flux is at the class C1 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 258) and in 9 active regions using 1K resolution (SN: 164) SDO/HMI images.

Region 13163 [S18W68] displayed slow development in the leading spot section as some penumbrae merged to form a larger penumbra. The region was mostly quiet.  C1 flare: C1.5 @ 13:05 UT
Region 13166 [S07W78] decayed slowly and was mostly quiet. C1 flare: C1.4 @ 00:03 (on December 21) UT
Region 13168 [S15W09] was quiet and stable.
Region 13169 [N20E33] had another day with several C flares and threw in an M class flare as well. The region lost area. C1 flare: C1.3 @ 20:01 UT
Region 13170 [S19E38] decayed slowly and was mostly quiet.
Region 13171 [N24E51] was mostly quiet and stable. C1 flare: C1.7 @ 03:06 UT

Spotted regions not observed (or interpreted differently) by SWPC:
S8106 [N26W01] was quiet and stable.
New region S8112 [S34E73] rotated into view with a mature spot.
New region S8113 [N21E19] was observed with tiny spots in an old plage area.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.0 01:25   13171 GOES16  
C2.3 04:03   13169 GOES16  
C4.4 04:10   13171 GOES16  
C6.6 05:45   13169 GOES16  
C5.0 06:09   13169 GOES16  
C2.5 07:49   13169 GOES16  
C8.1/1F 08:53 S19E49 13170 GOES16  
C2.1 09:54   13171 GOES16  
C6.5 13:56   13169 GOES16  
M1.1 14:06 N20E45 13169 GOES16  
C2.7 20:19   13169 GOES16  
C2.2 21:04   13163 GOES16  

Coronal mass ejections (CMEs)

December 18-20: 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 (CH1120) was Earth facing on December 17-18. Another recurrent northern hemisphere coronal hole (CH1121) was Earth facing on December 20.

Propagation

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

Forecast

Quiet to active geomagnetic conditions are expected for December 21-23 due to effects from CH1120 and CH1121.

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 colored red.

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
13163 2022.12.09
2022.12.10
10 29 17 S19W66 0380 EKI DKI

location: S18W68

13166 2022.12.10
2022.12.11
4 8 4 S08W78 0120 DAO CAO

location: S07W78

13167 2022.12.12
2022.12.13
3     N20W91 0020 CAO     rotated out of view
S8091 2022.12.13       N26W53            
13168 2022.12.13
2022.12.14
1 16 4 S15W10 0060 HSX CSO area: 0100

location: S15W09

S8097 2022.12.15       N21W24            
S8098 2022.12.16       S08W21            
S8099 2022.12.16       N23W57            
13169 2022.12.16
2022.12.17
14 57 23 N21E36 0220 ESC FSI

area: 0350

location: N20E33

13170 2022.12.17
2022.12.17
5 15 8 S20E37 0030 CRO CRO

location: S19E38

area: 0040

S8102 2022.12.17       N06E08           reversed polarities
S8103 2022.12.17       N08W34            
S8104 2022.12.17       S24W49            
13171 2022.12.18
2022.12.19
12 33 14 N24E52 0080 CAO DAI area: 0170

location: N24E51

S8106 2022.12.18   4 1 N26W01 0008   BXO  
S8107 2022.12.18       S15E26            
S8108 2022.12.19       N22E66          
S8109 2022.12.19       N09E27          
S8110 2022.12.19       S05E02         reversed polarities
S8111 2022.12.19       S24W33          
S8112 2022.12.20   1 1 S34E73 0070   HSX    
S8113 2022.12.20   5 2 N21E19 0010   AXX    
Total spot count: 49 168 74  
Sunspot number: 119 258 164  (total spot count + 10 * number of spotted regions)
Weighted SN: 87 206 112  (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): 132 142 131  

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
2021.05 75.3 77.1 21.2 25.8 (+1.0) 6.50
2021.06 79.4 81.8 25.0 27.6 (+1.8) 5.52
2021.07 81.0 83.6 34.3 31.4 (+3.8) 5.51
2021.08 77.7 79.7 22.0 35.4 (+4.0) 6.19
2021.09 87.0 88.2 51.3 40.2 (+4.8) 6.33
2021.10 88.9 88.3 37.4 45.2 (+5.0) 7.38
2021.11 86.2 84.4 34.8 50.8 (+5.6) 9.83
2021.12 103.0 99.8 67.5 55.9 (+5.1) 6.40
2022.01 103.8 100.5 55.3 60.1 (+4.2) 8.92
2022.02 109.1 106.5 60.9 64.8 (+4.7) 10.46
2022.03 117.0 115.8 78.6 68.9 (+4.1) 10.20
2022.04 130.8 131.7 84.0 73.1 (+4.2) 11.79
2022.05 133.8 136.8 96.5 77.3 (+4.2) 7.48
2022.06 116.1 119.8 70.3 (80.7 projected, +3.6) 8.20
2022.07 125.4 129.5 91.4 (85.7 projected, +5.0) 9.51
2022.08 114.2 117.1 75.4 (91.4 projected, +5.7) 10.92
2022.09 135.1 136.5 96.3 (96.3 projected, +4.9) 12.18
2022.10 133.5 132.7 95.4 (99.5 projected, +3.2) 11.16
2022.11 123.4 120.7 77.6 (102.3 projected, +2.8) 9.33
2022.12 147.5 (1)   73.7 (2A) / 116.4 (2B) / 116.0 (2C) (107.1 projected, +4.8) (8.2)
2023.01       (113.1 projected, +6.0)  
2023.02       (118.1 projected, +5.0)  
2023.03       (121.2 projected, +3.1)  
2023.04       (126.6 projected, +5.4)  
2023.05       (132.4 projected, +5.8)  
2023.11       (142.5 projected max SC25)  

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.