Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 9, 2024 at 06:55 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 8. Solar wind speed at SOHO ranged between 297 and 379 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels. A weak disturbance related to CH1196 arrived after noon and caused a gradual increase in disturbance levels towards the end of the day.

Solar flux density measured at 20h UT on 2.8 GHz was 176.2 - increasing 50.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 158.31. 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 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.5). Three hour interval K indices: 00001112 (planetary), 00012221 (Boulder), 00000124 (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 15 active regions using 2K resolution (SN: 335) and in 10 active regions using 1K resolution (SN: 192) SDO/HMI images.

Region 13536 [N06W34] decayed significantly and was mostly quiet.
Region 13537 [N17W32] decayed slowly and produced a few C flares.
Region 13538 [N20W54] gained a weak magnetic delta structure and was the most active region on the visible disk. C1 flares: C1.3 @ 06:51, C1.7 @ 08:07, C1.8 @ 14:02, C1.9 @ 15:02, C1.9 @ 22:42 UT
Region 13539 [N09W16] developed slowly and produced the largest flare of the day.
Region 13540 [S18E30] decayed slightly and was mostly quiet.
Region 13541 [S22E31] developed in the trailing spot section.
Region 13543 [S07W33] matured and was mostly quiet. C1 flares: C1.3 @ 05:01 UT
Region 13544 [N18E44] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9279 [N08W24] was quiet and stable.
S9291 [N14E09] reemerged with tiny spots.
S9293 [N27E11] was quiet and stable.
S9303 [S09E43] was quiet and stable.
New region S9307 [S06E81] rotated into view with a large spot.
New region S9308 [S24E63] was observed with a tiny spot in an old plage area.
New region S9309 [S10W78] emerged with tiny spots near the southwest limb.

AR 13534 behind the southwest limb was the likely source of a C1.8 flare at 13:05 UT

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.9 00:05   13537 GOES16  
C3.3 00:36   13538 GOES16  
C2.4 02:52 S19E45 13540 GOES16  
C2.8 08:24   13537 GOES16  
C7.3/2N 09:59 N10W10 13539 GOES16  
C2.1 11:01   13538 GOES16  
C2.9 15:21   13538 GOES16 simultaneous flare in AR S9279
SWPC incorrectly attributed this flare to AR 13542 (aka 13537)
C5.7 15:50   13538 GOES16  
C4.0 19:30   13538 GOES16  
C2.0 21:07   13538 GOES16  
C2.1 21:24   13538 GOES16  
C2.2 22:06   13538 GOES16 simultaneous flare in AR 13540
C2.4 23:16   13536 GOES16  
C2.7 23:31   13538 GOES16  

Coronal mass ejections (CMEs)

January 6-8: 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 southern hemisphere coronal hole (CH1196) was Earth facing on January 4-6.

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 9-11 with a chance of unsettled intervals on January 9-10 due to effects from CH1196.

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 26 11 N05W31 0120 EAI DAO beta-gamma

location: N06W34

area: 0080

S9279 2023.12.31   16 9 N08W24 0080   CAO  
13538 2023.12.31
2024.01.03
11 21 12 N25W54 0040 CAI DRI beta-delta

location: N20W54

area: 0100

13537 2024.01.01
2024.01.02
1 7 3 N18W35 0030 HAX CRO area: 0050

location: N17W32

S9291 2024.01.03   3   N14E09 0005   AXX    
S9292 2024.01.03       N21W47            
S9293 2024.01.04   3   N27E11 0005   BXO  
13541 2024.01.04
2024.01.05
3 17 9 S20E29 0050 DAI DAI location: S22E31

area: 0120

13540 2024.01.04
2024.01.05
15 30 19 S17E31 0290 DKI DAO

location: S18E30

S9296 2024.01.04       S13W26            
S9297 2024.01.04       S09E17          
S9298 2024.01.04       S15W49            
13539 2024.01.05 5 22 11 N11W12 0040 CAO DRI beta-gamma

location: N09W16

area: 0080

13542 2024.01.05 1     N19W29 0020 HAX       this is the eastern part of AR 13537
S9299 2024.01.05       N21W16            
13544 2024.01.05
2024.01.07
1 4 1 N19E47 0030 HAX HRX location: N18E44
S9301 2024.01.05       N35W16            
13543 2024.01.06
2024.01.07
12 23 16 S05W34 0080 DAI DAI area: 0240

location: S07W33

S9303 2024.01.06   8   S09E43 0012   BXO  
S9304 2024.01.06       N19W07            
S9305 2024.01.07       S13W34          
S9306 2024.01.07       S15W08          
S9307 2024.01.08   2 1 S06E81 0390   HHX    
S9308 2024.01.08   1   S24E63 0001   AXX    
S9309 2024.01.08   2   S10W78 0002   BXO    
Total spot count: 62 185 92  
Sunspot number: 152 335 192  (total spot count + 10 * number of spotted regions)
Weighted SN: 112 232 139  (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): 167 184 154  

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
2024.01 152.5 (1)   26.5 (2A) / 102.9 (2B) / 134.7 (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.

--------------------------------------------------------------------------------------

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.