Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 15, 2024 at 06:25 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

Recent activity

The geomagnetic field was quiet on January 14. Solar wind speed at SOHO ranged between 305 and 419 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 187.9 - increasing 26.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 158.01. 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: 6.1). Three hour interval K indices: 11122222 (planetary), 02222322 (Boulder), 21123444 (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 18 active regions using 2K resolution (SN: 354) and in 17 active regions using 1K resolution (SN: 251) SDO/HMI images.

Region 13540 [S18W50] was mostly quiet and stable. C1 flares: C1.9 @ 05:20 UT
Region 13541 [S22W47] has polarity intermixing and could produce a minor M class flare.
Region 13545 [S06E02] was mostly quiet, the large spot gained area. C1 flares: C1.9 @ 04:34 UT
Region 13546 [S24W17] decayed slowly and quietly.
Region 13547 [N18W22] decayed slowly and quietly.
Region 13548 [N10E17] decayed slowly and quietly.
Region 13549 [S21E36] developed slowly and has minor polarity intermixing. An M class flare is possible.
Region 13550 [S17W02] developed slowly and quietly.
Region 13551 [N27E28] was quiet and stable.
Region 13552 [S22W39] was quiet and stable.
Region 13553 [N05E56] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9303 [S12W32] was quiet and stable.
S9323 [N07E67] was quiet and stable.
S9324 [S20E58] was quiet and stable.
New region S9325 [S11E82] rotated into view with a few spots.
New region S9326 [S10W03] emerged with tiny spots.
New region S9327 [N12E37] emerged with a tiny spot.
New region S9328 [N21E34] emerged with tiny spots.

AR 13539 behind the northwest limb was the likely source of a C1.7 flare at 05:55 UT

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.2 00:22   13539 GOES16  
C2.0 01:38   13541 GOES16  
C2.0 02:56   13545 GOES16  
C2.0 04:39   13549 GOES16  
C2.6 07:19   13540 GOES16  
C2.8 07:30 S19W42 13541 GOES16  
C2.7 11:19   13541 GOES16  
C9.6 12:06     GOES16 moderate type II radio sweep
C7.3 13:08   13549 GOES16  
C3.1 14:02   13545 GOES16  
C2.8 14:28   13541 GOES16  
C5.8/1N 17:01 S22W43 13541 GOES16  
C3.2 18:44   13549 GOES16  
C3.0 19:53   13541 GOES16  
C2.2 20:42   13539 GOES16  

Coronal mass ejections (CMEs)

January 12-14: No obviously Earth directed CME observed.

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) rotated across the central meridian on January 13. Another positive polarity northern hemisphere coronal hole (CH1198) will be Earth facing on January 16-17.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet on January 15. Quiet to active conditions are possible on January 16-17 due to effects from CH1197.

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
13541 2024.01.04
2024.01.05
4 16 10 S22W48 0050 CSO DAI beta-gamma

area: 0130

location: S22W47

13540 2024.01.04
2024.01.05
16 28 15 S19W51 0110 DAI CSI location: S18W50
13539 2024.01.05 3     N13W96 0110 CAO     rotated out of view
13544 2024.01.05
2024.01.07
      N18W38          
S9303 2024.01.06   9 2 S12W32 0020   BXO  
13545 2024.01.08
2024.01.09
4 22 6 S06E02 0250 CHO CHO area: 0420
13546 2024.01.08
2024.01.09
9 14 5 S24W17 0010 BXI BXO

area: 0030

S9311 2024.01.09       N19W18            
13550 2024.01.09
2024.01.12
3 15 9 S18W03 0010 AXX CRO location: S17W02

area: 0040

13552 2024.01.09
2024.01.12
4 11 4 S22W39 0010 AXX CRO

area: 0020

13547 2024.01.10
2024.01.11
2 7 3 N18W23 0010 BXO CRO

area: 0025

location: N18W22

13551 2024.01.10
2024.01.12
3 7 4 N26E25 0010 BXO CRO area: 0020

location: N27E28

13548 2024.01.10
2024.01.12
5 7 3 N12E14 0040 CAO CAO location: N10E17
13549 2024.01.10
2024.01.12
7 16 9 S21E36 0250 CHI CHI location: S21E49

area: 0350

S9319 2024.01.12       N35E06            
13553 2024.01.13
2024.01.13
3 8 3 N05E54 0080 HSX CKO area: 0290

location: N05E56

S9321 2024.01.13       N11W07          
S9323 2024.01.13   3 2 N07E67 0100   HSX  
S9324 2024.01.13   2   S20E58 0002   BXO  
S9325 2024.01.14   2 2 S11E82 0170   HAX    
S9326 2024.01.14   4 2 S10W03 0010   BXO    
S9327 2024.01.14   1 1 N12E37 0004   AXX    
S9328 2024.01.14   2 1 N21E34 0003   BXO    
Total spot count: 63 174 81  
Sunspot number: 183 354 251  (total spot count + 10 * number of spotted regions)
Weighted SN: 107 241 148  (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): 201 195 201  

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
2024.01 166.7 (1)   61.4 (2A) / 135.9 (2B) / 153.0 (2C) (117.9 projected, -3.3) (5.1)
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.