Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 10, 2024 at 04:20 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 9, very weakly under the influence of effects from a low speed coronal hole stream associated with CH1196. Solar wind speed at SOHO ranged between 349 and 403 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 175.7 - increasing 40.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 158.27. 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: 5.1). Three hour interval K indices: 21211101 (planetary), 11311312 (Boulder), 50100103 (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 19 active regions using 2K resolution (SN: 384) and in 16 active regions using 1K resolution (SN: 259) SDO/HMI images.

Region 13536 [N06W49] decayed further and was mostly quiet.
Region 13537 [N17W45] decayed slowly and quietly.
Region 13538 [N20W67] developed slowly and produced several low level C flares. C1 flares: C1.6 @ 00:13, C1.4 @ 07:04, C1.4 @ 14:25, C1.7 @ 16:13 UT
Region 13539 [N09W29] developed slowly and was mostly quiet.
Region 13540 [S18E18] was mostly quiet and stable.  C1 flares: C1.9 @ 02:49, C1.3 @ 13:05 UT
Region 13541 [S22E18] decayed slowly and was mostly quiet. C1 flares: C1.4 @ 07:23 UT
Region 13543 [S07W48] decayed slowly and was mostly quiet.
Region 13544 [N18E30] decayed slowly and quietly.
New region 13545 [S06E68] rotated into view on January 8 and was numbered the next day by SWPC.
New region 13546 [S24E50] emerged on January 8 and developed further on January 9 when the region was numbered by SWPC. A weak magnetic delta structure may have formed and the region could be capable of minor M class flaring. C1 flares: C1.8 @ 19:05 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9279 [N08W39] decayed slowly and  was mostly quiet. C1 flares: C1.9 @ 05:51 UT
S9291 [N14W03] was quiet and stable.
S9293 [N27W01] was quiet and stable.
S9297 [S09E03] reemerged with tiny spots.
S9303 [S11E31] was quiet and stable.
New region S9310 [N05W02] emerged early in the day, then decayed after noon.
New region S9311 [N19E47] emerged with tiny spots.
New region S9312 [S16E63] emerged with tiny spots.
New region S9313 [S22E26] emerged with tiny spots to the east of AR 13541.

An active region at the southeast limb produced a C9.6 flare at 03:25 UT on January 10.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.1 01:09   13536 GOES16  
C3.1 04:10   13538 GOES16  
C2.5 08:50   13538 GOES16  
C3.8 11:23   13541 GOES16  
C2.0 15:03   13538 GOES16  
C2.7 17:10   13538 GOES16  
C3.9 19:35   13538 GOES16  
C2.0 21:42   13546 GOES16  
C2.2 21:58   13546 GOES16  
C2.1 22:56   13538 GOES16  
C2.4 23:56   S9279 GOES16  

Coronal mass ejections (CMEs)

January 7-8: 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]

No obvious coronal holes are currently in or near an Earth facing position.

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

The geomagnetic field is expected to be quiet on January 10-11. 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
13 11 3 N06W42 0170 EAO CRO

location: N06W49

area: 0030

S9279 2023.12.31   6 3 N08W39 0040   CRO  
13538 2023.12.31
2024.01.03
10 17 9 N20W67 0080 CAI DAI

area: 0150

13537 2024.01.01
2024.01.02
1 7 3 N18W47 0030 HAX HRX

location: N17W45

S9291 2024.01.03   2 1 N14W03 0003   BXO  
S9293 2024.01.04   4   N27W01 0010   BXO  
13541 2024.01.04
2024.01.05
5 17 12 S21E17 0080 DAI DRI location: S22E18
13540 2024.01.04
2024.01.05
14 26 19 S18E18 0240 CAO DSI  
S9296 2024.01.04       S13W39            
S9297 2024.01.04   3   S09E03 0005   AXX    
13539 2024.01.05 8 27 17 N10W27 0060 DAI DAI

location: N09W29

area: 0140

13542 2024.01.05 1     N18W43 0010 AXX       this is the eastern part of AR 13537
S9299 2024.01.05       N21W29            
13544 2024.01.05
2024.01.07
1 4 2 N18E32 0020 HSX AXX location: N18E30
S9301 2024.01.05       N35W29            
13543 2024.01.06
2024.01.07
8 18 12 S06W48 0110 DSO DSI

location: S07W48

S9303 2024.01.06   9   S11E31 0012   BXO  
S9304 2024.01.06       N19W20            
S9305 2024.01.07       S13W47            
S9306 2024.01.07       S15W21            
13545 2024.01.08
2024.01.09
1 4 3 S06E68 0190 HAX EHO area: 0330
13546 2024.01.08
2024.01.09
11 20 7 S24E50 0070 CAO DRI beta-gamma

area: 0100

S9310 2024.01.09   3 1 N05W02 0005   BXO    
S9311 2024.01.09   3 1 N19E47 0007   BXO    
S9312 2024.01.09   3 1 S16E63 0012   CRO    
S9313 2024.01.09   10 5 S22E26 0030   BXO    
Total spot count: 73 194 99  
Sunspot number: 183 384 259  (total spot count + 10 * number of spotted regions)
Weighted SN: 123 242 147  (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): 201 211 207  

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
2024.01 155.0 (1)   32.5 (2A) / 111.8 (2B) / 136.7 (2C) (117.9 projected, -3.3) (5.3)
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.