Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 12, 2024 at 07:30 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

Recent activity

The geomagnetic field was quiet on January 11, weakly under the influence of effects associated with CH1196. Solar wind speed at SOHO ranged between 408 and 524 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 192.5 - increasing 48.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 158.24. 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 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.4). Three hour interval K indices: 11222112 (planetary), 02233211 (Boulder), 22111103 (Andenes).

The background x-ray flux is at the class C2 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 16 active regions using 2K resolution (SN: 381) and in 14 active regions using 1K resolution (SN: 246) SDO/HMI images.

Region 13539 [N10W53] decayed in the leading spot section while development was observed in the trailing spots where a magnetic delta structure formed.
Region 13540 [S17W09] was mostly quiet and stable.
Region 13541 [S20W10] displayed no major changes and was mostly quiet.
Region 13543 [S07W76] decayed slowly and quietly.
Region 13544 [N18E04] was quiet and stable.
Region 13545 [S05E41] was quiet and stable.
Region 13546 [S24E25] has weak polarity intermixing and was mostly quiet.
New region 13547 [N19E18] emerged on January 10 with SWPC numbering the region the following day. Several C flares were observed.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9279 [N09W67] decayed and had only tiny spots by the end of the day
S9303 [S12E08] was quiet and stable.
S9310 [N06W17] was quiet and stable.
S9313 [S22W01] decayed slowly and quietly.
S9315 [N25E65] was quiet and stable.
S9316 [N11E56] developed slowly and produced several C flares. The region appears to be developed a magnetic delta structure.
S9317 [S20E73] rotated fully into view and was mostly quiet.
New region S9318 [S10W32] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.6 00:05   13539 GOES16 simultaneous flares in ARs 13538 and S9317
C4.3 00:54   S9317 GOES16 simultaneous flare in AR S9315
C5.2 01:12   13539 GOES16 simultaneous flare in AR S9317
C3.5 01:39   13538 GOES16  
C4.2 02:21   13538 GOES16  
C3.4 03:14   13538 GOES16  
C3.9 03:27   13538 GOES16  
C4.5 03:33   13539 GOES16  
C4.6 03:43 S25E35 13546 GOES16  
C3.1 04:15 N09W46 13539 GOES16  
C2.2 04:54   13546 GOES16  
C2.6 05:43   13546 GOES16  
C3.0 06:05   13541 GOES16 simultaneous flare in AR 13538
C7.8 06:19 N13W47 13539 GOES16  
C4.3 06:33   13538 GOES16  
C4.1 06:38   13538 GOES16  
C3.0 08:03   13541 GOES16  
C4.1 08:19   S9316 GOES16 incorrectly attributed to AR 13540 by SWPC
C6.4 09:01 N09W52 13539 GOES16 simultaneous flare in AR 13538
C4.5 09:25   13539 GOES16  
C3.0 10:09   13539 GOES16  
C3.9 10:42   13538 GOES16  
C4.2 11:34   13538 GOES16  
C3.2 11:51   13539 GOES16 simultaneous flare in AR 13538
C9.4 12:09   13538 GOES16  
M1.3 12:51   13538 GOES16  
C4.6 13:05   13538 GOES16  
C3.7 13:46   13539 GOES16  
C2.5 14:57   13547 GOES16  
C3.0 15:21   13539 GOES16  
C2.9 15:42   13547 GOES16  
C3.6 16:11   13538 GOES16  
C6.4 16:32   13538 GOES16  
C8.3 16:46   13538 GOES16  
C2.8 17:31   13547 GOES16  
C2.6 17:42   13547 GOES16  
M1.5 17:52   13539 GOES16  
C3.3 19:04   S9316 GOES16  
M1.2 19:23   13538 GOES16  
C7.8 20:30   13539 GOES16  
C2.6 21:07   13547 GOES16  
C3.6 22:54 N09W60 13539 GOES16  
C4.6 23:11   S9316 GOES16 simultaneous flares in ARs 13543 and 13539
C3.4 23:41   S9316 GOES16  

Coronal mass ejections (CMEs)

January 10-11: 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 or 13.

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 January 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 12. Quiet to active conditions are possible on January 12-14 due to to CME effects.

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
1     N07W72 0010 AXX    

location: N05W76

spotless

S9279 2023.12.31   2   N09W67 0005   BXO  
13537 2024.01.01
2024.01.02
      N18W66        

location: N17W71

S9291 2024.01.03       N15W33          
S9293 2024.01.04       N27W27            
13541 2024.01.04
2024.01.05
15 30 14 S22W04 0100 ESI DRI beta-gamma

location: S20W10

SWPC data appears to include AR S9313

13540 2024.01.04
2024.01.05
12 23 8 S18W10 0150 CAO CAO location: S17W09
S9297 2024.01.04       S07W22          
13539 2024.01.05 13 36 18 N10W56 0230 DAI DAC

beta-delta

location: N10W53

13542 2024.01.05       N18W71           this was the eastern part of AR 13537
S9299 2024.01.05       N21W55            
13544 2024.01.05
2024.01.07
1 8 2 N18E04 0010 AXX CRO area: 0020
13543 2024.01.06
2024.01.07
4 6 2 S06W78 0050 CSO CRO

location: S07W76

S9303 2024.01.06   14 5 S12E08 0020   BXO  
S9304 2024.01.06       N19W46            
S9306 2024.01.07       S15W47            
13545 2024.01.08
2024.01.09
1 8 5 S06E40 0150 HSX CHO area: 0380

location: S05E41

13546 2024.01.08
2024.01.09
11 29 16 S24E22 0070 DAI DRI beta-gamma

area: 0160

location: S24E25

S9310 2024.01.09       N06W30          
S9311 2024.01.09       N19E21            
S9312 2024.01.09   10 3 S16E36 0030   DRO  
S9313 2024.01.09   22 13 S22W01 0100   DAO  
13547 2024.01.10
2024.01.11
3 13 8 N19E19 0040 DSO DAO beta-gamma

location: N19E18

area: 0120

S9315 2024.01.10   2 2 N25E65 0015   DRO  
S9316 2024.01.10   11 7 N11E56 0060   DRI beta-delta?
S9317 2024.01.10   6 3 S20E73 0330   DHO  
S9318 2024.01.11   1   S10W32 0002   AXX    
Total spot count: 61 221 106  
Sunspot number: 151 381 246  (total spot count + 10 * number of spotted regions)
Weighted SN: 96 282 167  (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): 166 210 197  

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
2024.01 161.3 (1)   43.2 (2A) / 121.8 (2B) / 144.9 (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.