Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 11, 2024 at 04:25 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 (January 1, 2024)
Solar cycle Solar cycles 23-25 (January 1, 2024) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (January 1, 2024) 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, 2024) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (January 1, 2024) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (January  3, 2024) 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
Calculating the Strength of Solar Cycle 25 Using 365-day Smoothing (new)

Recent activity

The geomagnetic field was quiet on January 10, weakly under the influence of effects from a low speed coronal hole stream associated with CH1196 (phi was in a positive sector all day) . Solar wind speed at SOHO ranged between 364 and 440 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels.

Solar flux density measured at 20h UT on 2.8 GHz was 186.0 - increasing 38.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 158.25. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 158.71 on June 27, 2023). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.4). Three hour interval K indices: 22122122 (planetary), 12133221 (Boulder), 11002024 (Andenes).

The background x-ray flux is at the class C3 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 21 active regions using 2K resolution (SN: 399) and in 19 active regions using 1K resolution (SN: 298) SDO/HMI images.

Region 13536 [N05W63] decayed further and had only tiny spots by the end of the day.
Region 13537 [N17W58] decayed slowly and quietly.
Region 13538 [N21W80] developed further becoming a compact region. The region produced several C flares and an M1.9 flare.
Region 13539 [N09W42] developed a magnetic delta structure in the northern part of the leading spot section. M flares are possible.
Region 13540 [S18E04] was mostly quiet and stable.
Region 13541 [S21E04] gained spots and was mostly quiet.
Region 13543 [S07W62] decayed slowly and quietly.
Region 13544 [N18E17] decayed slowly and quietly.
Region 13545 [S06E54] was quiet and stable.
Region 13546 [S24E37] developed slowly and was mostly quiet.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9279 [N09W52] decayed slowly and  was mostly quiet.
S9291 [N15W20] was quiet and stable.
S9297 [S07W09] was quiet and stable.
S9303 [S10E18] was quiet and stable.
S9310 [N06W17] was quiet and stable.
S9313 [S22E12] developed further and was mostly quiet.
New region S9314 [N19E33] emerged with several spots.
New region S9315 [N24E78] rotated into view with small and tiny spots.
New region S9316 [N11E68] rotated into view with a tiny spot.
New region S9317 [S21E86] rotated partly into view with a large leader spot. The region was very active during the day and produced many C flares and an M1.4 flare.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.0 00:34   13538 GOES16  
C2.2 01:04   13538 GOES16  
C2.1 01:15   S9315 GOES16  
C3.3 02:12   13538 GOES16 simultaneous flare in AR 13546
C3.2 02:46   13538 GOES16  
C5.4 03:16   S9317 GOES16  
C9.6 03:25   13538 GOES16  
C5.7 04:05   13541 GOES16 simultaneous flare in AR S9317
C7.0 04:33   13538 GOES16  
C3.0 05:03   S9317 GOES16  
C7.0 05:45   S9317 GOES16  
C4.1 06:26   13538 GOES16  
C6.6 06:56   13538 GOES16  
C6.2 06:59   S9279 GOES16  
C2.1 07:48   S9315 GOES16  
C2.8 08:51   13536 GOES16  
C3.5 09:03   13539 GOES16  
C3.4 09:31   13538 GOES16  
C3.4 09:49   13538 GOES16  
C5.2 10:06   13538 GOES16  
C2.4 10:29   S9317 GOES16  
C3.1 10:57   13538 GOES16  
C2.2 11:38   13538 GOES16  
C2.5 11:54   13539 GOES16  
M1.4 12:55   S9317 GOES16  
C4.5 14:31     GOES16  
C3.7 14:46   S9317 GOES16  
C4.0 15:15   S9317 GOES16  
C2.3 16:07   13541 GOES16  
C3.1 16:44     GOES16  
C3.4 16:59   S9317 GOES16  
C3.6 17:22   S9317 GOES16  
C2.8 17:48   13538 GOES16  
C2.8 18:02   13538? GOES16  
C2.8 18:21   13539 GOES16  
C6.5 19:07   S9279 GOES16  
C3.0 20:00   13538 GOES16  
C5.6 20:41 behind northeast limb   GOES16 simultaneous flare in AR 13546
C2.9 21:31   13545 GOES16  
C6.0 22:01   13538 GOES16  
C3.9 22:19   13539 GOES16  
C3.2 22:58   13539 GOES16  
M1.9 23:28   13538 GOES16 simultaneous flare in AR 13541

Coronal mass ejections (CMEs)

January 8, 10: No obviously Earth directed CME observed.
January 9: A partial halo CME was observed after a large filament eruption in the southeast quadrant. A weak shock from this CME is possible on January 12.

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 positive polarity northern hemisphere coronal hole (CH1197) will likely rotate across the central meridian on Janaurey 13.

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. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on January 11. Weak CME influences are possible on January 12-13.

Coronal holes (1) Coronal mass ejections (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
13536 2023.12.31
2023.12.31
4 2 1 N06W57 0060 DAO AXX

location: N05W63

area: 0005

S9279 2023.12.31   6 2 N09W52 0020   CRO  
13538 2023.12.31
2024.01.03
10 6 4 N20W81 0200 CAO DAC

area: 0310

location: N21W80

13537 2024.01.01
2024.01.02
1 3 3 N18W61 0030 HAX HRX

location: N17W58

area: 0025

S9291 2024.01.03   4 3 N15W20 0010   AXX  
S9293 2024.01.04       N27W14          
13541 2024.01.04
2024.01.05
24 25 12 S23E07 0060 EAI DRI location: S21E04

SWPC data is suspect, maybe they are including AR S9313??

13540 2024.01.04
2024.01.05
14 23 11 S18E04 0240 CAO CSO  
S9296 2024.01.04       S13W52            
S9297 2024.01.04   3 2 S07W09 0010   BXO  
13539 2024.01.05 9 25 21 N10W41 0220 DAO DAI

beta-gamma-delta

location: N09W42

13542 2024.01.05       N18W57           this was the eastern part of AR 13537
S9299 2024.01.05       N21W42            
13544 2024.01.05
2024.01.07
1 5 3 N18E18 0020 HSX BXO location: N18E17
S9301 2024.01.05       N35W42            
13543 2024.01.06
2024.01.07
8 12 4 S06W63 0190 DSO DAO

location: S07W62

area: 0070

S9303 2024.01.06   9 2 S10E18 0012   BXO  
S9304 2024.01.06       N19W33            
S9306 2024.01.07       S15W34            
13545 2024.01.08
2024.01.09
1 5 3 S06E52 0190 HAX CHO area: 0330

location: S06E54

13546 2024.01.08
2024.01.09
11 26 18 S24E36 0070 CAI DRI beta-gamma

area: 0150

location: S24E37

S9310 2024.01.09   2 1 N06W17 0004   AXX  
S9311 2024.01.09       N19E34          
S9312 2024.01.09   4 1 S16E50 0007   BXO  
S9313 2024.01.09   16 11 S22E12 0120   DAO  
S9314 2024.01.10   9 5 N19E33 0050   DRO    
S9315 2024.01.10   2 1 N24E78 0015   CRO    
S9316 2024.01.10   1   N11E68 0001   AXX    
S9317 2024.01.10   1   S21E85 0180   HSX    
Total spot count: 83 189 108  
Sunspot number: 183 399 298  (total spot count + 10 * number of spotted regions)
Weighted SN: 133 247 166  (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): 201 219 238  

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 (SC24 solar max) 7.88
2017.09 91.3 92.3 43.6 18.2 (-1.3) 18.22
(SC24 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
2022.05 133.8 136.8 96.5 77.4 (+4.4) 7.48
2022.06 116.1 119.8 70.3 81.1 (+3.7) 8.20
2022.07 125.4 129.5 91.4 86.7 (+5.6) 9.51
2022.08 114.2 117.1 74.6 92.6 (+5.9) 10.92
2022.09 135.1 136.5 96.0 96.5 (+3.9) 12.18
2022.10 133.5 132.7 95.5 98.9 (+2.4) 11.16
2022.11 123.4 120.7 80.5 101.2 (+2.3) 9.33
2022.12 147.9 143.4 112.8 106.7 (+5.5) 10.99
2023.01 182.4 176.6 144.4 113.3 (+6.6) 8.73
2023.02 167.2 163.2 111.3 117.8 (+3.5) 14.48
(current
SC25 peak)
2023.03 157.2 155.6 123.3 121.0 (+3.2) 14.42
2023.04 145.4 146.4 97.6 122.7 (+1.7) 13.40
2023.05 155.6 159.2 137.4 123.9 (+1.2) 10.67
2023.06 161.7 166.8 160.5 125.0 (+1.1)
(SC25 solar max candidate)
8.95
2023.07  176.4 182.2 159.1 (124.6 projected, -0.4) 8.15
2023.08  153.7 157.6 114.8 (124.1 projected, -0.5) 7.19
2023.09  154.4 156.0 133.6 (123.8 projected, -0.3) 14.26
2023.10  142.8 141.9 99.4 (124.6 projected, +0.8) 8.16
2023.11 153.5 150.2 105.4 (124.6 projected, +0.0) 12.20
2023.12 151.1 146.4 114.2 (121.2 projected, -3.4) 9.60
2024.01 158.1 (1)   38.4 (2A) / 118.9 (2B) / 142.1 (2C) (117.9 projected, -3.3) (5.4)
2024.02       (117.1 projected, -0.8)  
2024.03       (116.6 projected, -0.5)  
2024.04       (116.6 projected, +0.0)  
2024.05       (117.0 projected, -0.8)  
2024.06       (114.9 projected, -2.1)  

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: WDC-SILSO, Royal Observatory Of Belgium, Brussels

Solar cycles 24-25

Smoothed SF and sunspot numbers

Update on the progress of solar cycle 25 as of January 3, 2024

The relatively low solar activity during the last months of 2023 significantly increased the possibility that solar cycle 25 has already peaked. Whether the first peak in June 2023 will be the actual solar max will not be known for some time. Due to the relatively high solar activity early in 2023 it is unlikely there will be another solar max candidate, if at all, until at least May 2024. Both the northern and southern polar fields, as well as the averaged total field, have already reversed polarities.

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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.