Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 1, 2023 at 10:50 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 (January 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (January 1, 2023) 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 (January 1, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (January 1, 2023) 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 to active on December 31 under the influence of effects from CH1122. Solar wind speed at SOHO ranged between 488 and 714 km/sec. The high latitude magnetometer at Andenes recorded unsettled to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 165 - increasing 21 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 124.38). The Potsdam WDC planetary A index was 16 (STAR Ap - based on the mean of three hour interval ap indices: 15.9). Three hour interval K indices: 33323234 (planetary), 33223333 (Boulder), 54434456 (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 11 active regions using 2K resolution (SN: 246) and in 7 active regions using 1K resolution (SN: 136) SDO/HMI images.

Region 13172 [S37W57] decayed slowly and quietly.
Region 13173 [N23W42] decayed slowly and quietly.
Region 13176 [N18W02] decayed slowly losing spots and area. C1 flares: C1.7 @ 01:33, C1.6 @ 23:55 UT
Region 13177 [S18E31] was mostly quiet and stable.
Region 13179 [N13W36] matured and was mostly quiet.

Spotted regions not observed (or interpreted differently) by SWPC:
S8133 [N16E55] decayed slowly and quietly.
S8135 [N21E58] decayed slowly and remains capable of producing a minor M class flare. C1 flares: C1.8 @ 09:44 UT
S8137 [S26E32] was quiet and stable.
New region S8139 [S19E82] rotated into view with a mature spot.
New region S8140 [N28E30] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C7.9 02:48 N20E70 S8135 GOES16  
C2.1 04:39   13176 GOES16  
C2.0 05:09   S8135 GOES16  
C2.0 10:53   13179 GOES16  
C4.9 11:34 N22E61 S8135 GOES16  
C2.2 16:28   13176 GOES16  
C2.0 17:25   13171 GOES16  
C2.0 17:49   S8135 GOES16  
C3.5 20:55   13177 GOES16  
C2.4 21:32   13179 GOES16  
C9.1 21:48   S8135 GOES16  

Coronal mass ejections (CMEs)

December 29-31: 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 trans equatorial coronal hole (CH1123) will likely become Earth facing on January 1-2.

Propagation

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

Forecast

Quiet to unsettled conditions are expected for January 1 due to lingering effects from CH1122. Mostly quiet conditions are likely on January 2-3. Quiet to minor storm conditions are expected on January 4-5 due to effects from CH1123.

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
13172 2022.12.20
2022.12.21
  1   S35W64 0001   AXX location: S37W57
13173 2022.12.22
2022.12.22
1 4 3 N24W42 0020 HRX BXO

location: N23W42

13175 2022.12.24
2022.12.25
      S20W25         location: S21W20
13176 2022.12.25
2022.12.26
12 45 20 N20W03 0430 EKO EAI beta-gamma

location: N18W02

13177 2022.12.27
2022.12.28
6 29 13 S18E31 0310 DAC DSI  
S8128 2022.12.27       N05W21            
13179 2022.12.28
2022.12.29
7 29 19 N14W37 0360 DKI DAI

location: N13W36

S8133 2022.12.29   5 3 N16E55 0120   CSO  
S8134 2022.12.29       S38W25            
13180 2022.12.30 6     N19E56 0210   DAO     SWPC consider AR S8133 and S8135 to be one region
S8135 2022.12.30   14 7 N21E58 0190   DAO  
S8136 2022.12.30       N31W01          
S8137 2022.12.30   5   S26E32 0006   BXO  
S8138 2022.12.30       S01W50          
S8139 2022.12.31   2 1 S19E82 0170   HAX    
S8140 2022.12.31   1   N28E30 0001   AXX    
S8141 2022.12.31   1   N18W14 0002   AXX    
Total spot count: 32 136 66  
Sunspot number: 82 246 136  (total spot count + 10 * number of spotted regions)
Weighted SN: 65 171 101  (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): 90 135 109  

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 81.0 (+3.7) 8.20
2022.07 125.4 129.5 91.4 (86.1 projected, +5.1) 9.51
2022.08 114.2 117.1 75.4 (91.5 projected, +5.4) 10.92
2022.09 135.1 136.5 96.3 (96.4 projected, +4.9) 12.18
2022.10 133.5 132.7 95.4 (99.6 projected, +3.2) 11.16
2022.11 123.4 120.7 77.6 (102.4 projected, +2.8) 9.33
2022.12 147.9 143.4 113.1 (107.2 projected, +4.8) 11.2
2023.01 (1)   (2A/2B) / 135.6 (2C) (113.2 projected, +6.0) ()
2023.02       (118.2 projected, +5.0)  
2023.03       (121.3 projected, +3.1)  
2023.04       (126.7 projected, +5.4)  
2023.05       (132.5 projected, +5.8)  
2023.06       (135.7 projected, +3.2)  
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.